CD Actual 13/CDA13.ISO/DOC/HOWTO/ETHERNET.GZ/ETHERNET

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  Linux Ethernet-Howto
  Paul Gortmaker, Editor.
  v2.5, 18 November 1995

  This is the Ethernet-Howto, which is a compilation of information
  about which ethernet devices can be used for Linux, and how to set
  them up. It hopefully answers all the frequently asked questions about
  using ethernet cards with Linux. Note that this Howto is focused on
  the hardware and low level driver aspect of the ethernet cards, and
  does not cover the software end of things. See the NET2-Howto for that
  stuff.

  1.  Introduction

  The Ethernet-Howto covers what cards you should and shouldn't buy; how
  to set them up, how to run more than one, and other common problems
  and questions. It contains detailed information on the current level
  of support for all of the most common ethernet cards available.  It
  does not cover the software end of things, as that is covered in the
  NET-2 Howto. Also note that general non-Linux specific questions about
  Ethernet are not (or at least they should not be) answered here. For
  those types of questions, see the excellent amount of information in
  the comp.dcom.lans.ethernet FAQ. You can FTP it from dorm.rutgers.edu
  in the directory /pub/novell/info_and_docs/

  This present revision covers distribution kernels up to and including
  v1.2.13. Information pertaining to development kernels up to version
  1.3.42 is also documented.

  The Ethernet-Howto is edited and maintained by:

       Paul Gortmaker, [e-mail]

  The primary source of the information for the initial Ethernet-Howto
  was from:

       Donald J. Becker, [e-mail]

  who we have to thank for writing the vast majority of ethernet card
  drivers that are presently available for Linux. He also is the
  original author of the NFS server too. Thanks Donald! We owe ya one!
  :-)

  Net-surfers may wish to check out the following URL:

  Donald Becker
  <http://cesdis.gsfc.nasa.gov/pub/people/becker/whoiam.html>

  1.1.  New Versions of this Document

  New versions of this document can be retrieved via anonymous FTP from:

  Sunsite HOWTO Archive <ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/>

  and various Linux ftp mirror sites. Updates will be made as new
  information and/or drivers becomes available. If this copy that you
  are reading is more than 4 months old, it is either out of date, or it
  means that I have been lazy and haven't updated it.  This document was
  produced by using the SGML system that was specifically set up for the
  Linux Howto project, and there are various output formats available,
  including, postscript, dvi, ascii, html, and soon TeXinfo.
  I would recommend viewing it in the html (via a WWW browser) or the
  Postscript/dvi format. Both of these contain cross-references that are
  lost in the ascii translation.

  If you want to get the official copy off sunsite, here is URL.

  Ethernet-HOWTO <http://sunsite.unc.edu/mdw/HOWTO/Ethernet-HOWTO.html>

  If minor additions and changes have been made, you can view the latest
  working copy from this URL.

  Working Copy <http://rsphy1.anu.edu.au/~gpg109/Ethernet-HOWTO.html>

  1.2.  Using the Ethernet-Howto

  As this guide is getting bigger and bigger, you probably don't want to
  spend the rest of your afternoon reading the whole thing. And you
  don't have to read it all. If you haven't got an ethernet card, then
  you will want to start with ``What card should I buy...''  to see what
  you should buy, and what you should avoid. If you have already got an
  ethernet card, but are not sure if you can use it with Linux, then you
  will want to read ``Vendor Specific...''  which contains specific
  information on each manufacturer, and their cards. If you are having
  trouble with your card, then you will want to read the specific
  information about your card mentioned above, and the troubleshooting
  information in ``the FAQ section''.  If you are interested in some of
  the technical aspects of the device drivers, then you can find that
  information in ``Technical Information''

  1.3.  Disclaimer and Copyright

  This document is not gospel. However, it is probably the most up to
  date info that you will be able to find. Nobody is responsible for
  what happens to your hardware but yourself. If your ethercard or any
  other hardware goes up in smoke (...nearly impossible!)  we take no
  responsibility. ie. THE AUTHORS ARE NOT RESPONSIBLE FOR ANY DAMAGES
  INCURRED DUE TO ACTIONS TAKEN BASED ON THE INFORMATION INCLUDED IN
  THIS DOCUMENT.

  This document is Copyright (c) 1993, 1994, 1995 by Donald Becker and
  Paul Gortmaker. Permission is granted to make and distribute verbatim
  copies of this manual provided the copyright notice and this
  permission notice are preserved on all copies.

  Permission is granted to copy and distribute modified versions of this
  document under the conditions for verbatim copying, provided that this
  copyright notice is included exactly as in the original, and that the
  entire resulting derived work is distributed under the terms of a
  permission notice identical to this one.

  Permission is granted to copy and distribute translations of this
  document into another language, under the above conditions for
  modified versions.

  If you are intending to incorporate this document into a published
  work, please contact me, and I will make an effort to ensure that you
  have the most up to date information available. In the past, out of
  date versions of the Linux howto documents have been published, which
  caused the developers undue grief from being plagued with questions
  that were already answered in the up to date versions.

  2.  What card should I buy for Linux?

  The answer to this question depends heavily on exactly what you intend
  on doing with your net connection, and how much traffic it will see.

  If you only expect a single user to be doing the occasional ftp
  session or WWW connection, then an old 8 bit wd8003 card will keep you
  happy.

  If you intend to set up a server, and you require the CPU overhead of
  Rx'ing and Tx'ing ether packets to be kept at a minimum, you probably
  want to look at one of the newer PCI cards with the DEC 21040 chip, or
  the AMD PCnet-PCI chip.

  If you fall somewhere in the middle of the above, then any one of the
  16 bit ISA cards with stable drivers will do the job for you.

  2.1.  So What Drivers are Stable?

  Of the 16 bit ISA cards, the following drivers are very mature, and
  you shouldn't have any problems if you buy a card that uses these
  drivers.

  SMC-Ultra/EtherEZ, WD80x3, 3c509, 3c503/16, Lance, NE2000.

  This is not to say that all the other drivers are unstable.  It just
  happens that the above are the oldest and most used of all the linux
  drivers, making them the safest choice.

  Note that some el-cheapo motherboards can have trouble with the bus-
  mastering that the lance cards do, and some el-cheapo NE2000 clones
  can have trouble getting detected at boot.

  As for PCI cards, the PCnet-PCI cards that use the lance driver are a
  safe choice (except for the Boca cards as they have hardware flaws).
  The Allied Telsyn AT2450 is a PCnet-PCI implementation that is known
  to work well.

  The DEC 21040 `tulip' driver and the 3c59x `vortex' driver are
  relatively new drivers, but have proven themselves to be quite stable
  already. (The newer 21041 based cards may be slightly problematic at
  the moment, but this will no doubt be resolved quickly.)

  2.2.  Eight bit vs 16 bit Cards

  You probably can't buy a new 8 bit ISA ethercard anymore, but you will
  find lots of them turning up at computer swap meets and the like for
  the next few years, at very low prices.  This will make them popular
  for ``home-ethernet'' systems.

  Some 8 bit cards that will provide adequate performance for light to
  average use are the wd8003, the 3c503 and the ne1000.  The 3c501
  provides poor performance, and these poor 10 year old relics of the XT
  days should be avoided.

  The 8 bit data path doesn't hurt performance that much, as you can
  still expect to get about 500 to 800kB/s ftp download speed to an 8
  bit wd8003 card (on a fast ISA bus) from a fast host.  And if most of
  your net-traffic is going to remote sites, then the bottleneck in the
  path will be elsewhere, and the only speed difference you will notice
  is during net activity on your local subnet.
  2.3.  32 Bit / VLB / PCI Ethernet Cards

  There aren't many 32 bit ethercard device drivers because there aren't
  that many 32 bit ethercards.  There aren't many 32 bit ethercards out
  there because a 10Mbs network doesn't justify spending the 5x price
  increment for the 32 bit interface. (For a 100Mbs network, it is a
  different story though.)

  See ``Programmed I/O vs. ...'' as to why having an ethercard on an
  8MHz ISA bus is really not a bottleneck. Even though having the
  ethercard on a fast bus won't necessarily mean faster transfers, it
  will usually mean reduced CPU overhead, which is good for multi-user
  systems.

  AMD has the 32 bit PCnet-VLB and PCnet-PCI chips.  See ``AMD
  PCnet-32'' for info on the 32 bit versions of the LANCE / PCnet-ISA
  chip.

  The DEC 21040 PCI chip is another option (see ``DEC 21040'') for
  power-users.  Many manufacturers produce cards that use this chip.

  3Com's `Vortex' PCI cards are also another option, and the price is
  quite cheap if you can get one under their evaluation deal while it
  lasts.  (see ``3c590/3c595'')

  2.4.  Available 100Mbs Cards and Drivers

  The present list of supported 100Mbs hardware is as follows: cards
  with the DEC 21140 chip; the 3c595 Vortex card; and the HP 100VG ANY-
  LAN. The drivers for the first two are quite stable, but feedback on
  the HP driver has been low so far as it has only been around since
  early 1.3.x kernels.

  The EtherExpressPro10/100 is not presently supported.  Getting
  documentation out of intel is difficult to impossible, which is the
  main reason.

  The 21140 100Base-? chip is supported with the same driver as its
  10Mbs counterpart, the 21040. SMC's 100Mbs EtherPower PCI card uses
  this chip. As with the 21040, you have a choice of two drivers to pick
  from.

  Also have a look at the information on Donald's WWW site, at the
  following URL:

  100Mbs Ethernet <http://cesdis.gsfc.nasa.gov/linux/misc/100mbs.html>

  Donald has been doing most of his work with the SMC EtherPower-10/100
  cards, and reports getting about 4.6MB/s application to application
  with TCP on P5-100 Triton machines.

  (See ``3c595'' and ``DEC 21140'' for more details.)

  For 100VG information, see Donald's 100VG Page
  <http://cesdis.gsfc.nasa.gov/linux/drivers/100vg.html>

  You may also be interested in looking at:

  Dan Kegel's Fast Ethernet Page <http://alumni.caltech.edu/~dank/fe/>

  2.5.  Programmed I/O vs. Shared Memory vs. DMA

  Ethernet is 10Mbs. (Don't be pedantic, 3Mbs and 100Mbs don't count.)
  If you can already send and receive back-to-back packets, you just
  can't put more bits over the wire. Every modern ethercard can receive
  back-to-back packets. The Linux DP8390 drivers come pretty close to
  sending back-to-back packets (depending on the current interrupt
  latency) and the 3c509 and AT1500 hardware has no problem at all
  automatically sending back-to-back packets.

  The ISA bus can do 5.3MB/sec (42Mb/sec), which sounds like more than
  enough. You can use that bandwidth in several ways:

  2.5.1.  Programmed I/O (e.g. NE2000, HP)

  Pro: Doesn't use any constrained system resources, just a few I/O
  registers, and has no 16M limit.

  Con: Usually the slowest transfer rate, the CPU is waiting the whole
  time, and interleaved packet access is usually difficult to
  impossible.

  2.5.2.  Shared memory (e.g. WD80x3, SMC-Ultra, 3c503)

  Pro: Simple, faster than programmed I/O, and allows random access to
  packets. The linux drivers compute the checksum of incoming IP packets
  as they are copied off the card, resulting in a further reduction of
  CPU usage vs. an equivalent PIO card.

  Con: Uses up memory space (a big one for DOS users, only a minor issue
  under Linux), and it still ties up the CPU.

  2.5.3.  Slave (normal) Direct Memory Access (e.g. none for Linux!)

  Pro: Frees up the CPU during the actual data transfer.

  Con: Checking boundary conditions, allocating contiguous buffers, and
  programming the DMA registers makes it the slowest of all techniques.
  It also uses up a scarce DMA channel, and requires aligned low memory
  buffers.

  2.5.4.  Bus Master Direct Memory Access (e.g. LANCE, DEC 21040)

  Pro: Frees up the CPU during the data transfer, can string together
  buffers, can require little or no CPU time lost on the ISA bus.

  Con: Requires low-memory buffers and a DMA channel. Any bus-master
  will have problems with other bus-masters that are bus-hogs, such as
  some primitive SCSI adaptors. A few badly-designed motherboard
  chipsets have problems with bus-masters. And a reason for not using
  any type of DMA device is using a 486 processor designed for plug-in
  replacement of a 386: these processors must flush their cache with
  each DMA cycle. (This includes the Cx486DLC, Ti486DLC, Cx486SLC,
  Ti486SLC, etc.)

  2.6.  Type of cable that your card should support

  If you are setting up a small ``personal'' network, you will probably
  want to use thinnet or thin ethernet cable. This is the style with the
  standard BNC connectors. See ``Cables, Coax...''  for other concerns
  with different types of ethernet cable.

  Most ethercards also come in a `Combo' version for only $10-$20 more.
  These have both twisted pair and thinnet transceiver built-in,
  allowing you to change your mind later.

  The twisted pair cables, with the RJ-45 (giant phone jack) connectors
  is technically called 10BaseT. You may also hear it called UTP
  (Unsheilded Twisted Pair).

  The thinnet, or thin ethernet cabling, (RG-58 coaxial cable) with the
  BNC (metal push and turn-to-lock) connectors is technically called
  10Base2.

  The older thick ethernet (10mm coaxial cable) which is only found in
  older installations is called 10Base5.

  Large corporate installations will most likely use 10BaseT instead of
  10Base2. 10Base2 does not offer an easy upgrade path to the new
  upcoming 100Base-whatever.

  3.  Frequently Asked Questions

  Here are some of the more frequently asked questions about using Linux
  with an Ethernet connection. Some of the more specific questions are
  sorted on a `per manufacturer basis'.  However, since this document is
  basically `old' by the time you get it, any `new' problems will not
  appear here instantly. For these, I suggest that you make efficient
  use of your newsreader. For example, nn users would type

       nn -xX -s'3c'

  to get all the news articles in your subscribed list that have `3c' in
  the subject. (ie. 3com, 3c509, 3c503, etc.)  The moral: Read the man
  page for your newsreader.

  3.1.  Alpha Drivers -- Getting and Using them

  I heard that there is an updated or alpha driver available for my
  card. Where can I get it?

  The newest of the `new' drivers can be found on Donald's new ftp site:
  cesdis.gsfc.nasa.gov in the /pub/linux/ area. Things change here quite
  frequently, so just look around for it.  There is still all the stuff
  on the old ftp site ftp.super.org in /pub/linux, but this is not being
  actively maintained, and hence will be of limited value to most
  people.

  Note that most of the `useable' alpha drivers have been included in
  the standard kernel source tree. When running make config you will be
  asked if you want to be offered ALPHA test drivers.

  Now, if it really is an alpha, or pre-alpha driver, then please treat
  it as such. In other words, don't complain because you can't figure
  out what to do with it. If you can't figure out how to install it,
  then you probably shouldn't be testing it.  Also, if it brings your
  machine down, don't complain. Instead, send us a well documented bug
  report, or even better, a patch!

  People reading this while net-surfing may want to check out:

  Don's Linux Home Page
  <http://cesdis.gsfc.nasa.gov/pub/linux/linux.html>

  for the latest dirt on what is new and upcoming.

  3.2.  Using More than one Ethernet Card per Machine

  What needs to be done so that Linux can run two ethernet cards?

  The hooks for multiple ethercards are all there.  However, note that
  only one ethercard is auto-probed for by default.  This avoids a lot
  of possible boot time hangs caused by probing sensitive cards.

  There are two ways that you can enable auto-probing for the second
  (and third, and...) card. The easiest method is to pass boot-time
  arguments to the kernel, which is usually done by LILO. Probing for
  the second card can be achieved by using a boot-time argument as
  simple as ether=0,0,eth1. In this case eth0 and eth1 will be assigned
  in the order that the cards are found at boot.  Say if you want the
  card at 0x300 to be eth0 and the card at 0x280 to be eth1 then you
  could use

       LILO: linux ether=5,0x300,eth0 ether=15,0x280,eth1

  The ether= command accepts more than the IRQ + i/o + name shown above.
  Please have a look at ``Passing Ethernet Arguments...''  for the full
  syntax, card specific parameters, and LILO tips.

  These boot time arguments can be made permanent so that you don't have
  to re-enter them every time. See the LILO configuration option
  `append' in the LILO manual.

  The second way (not recommended) is to edit the file Space.c and
  replace the 0xffe0 entry for the i/o address with a zero. The 0xffe0
  entry tells it not to probe for that device -- replacing it with a
  zero will enable autoprobing for that device.  If you really need more
  than four ethernet cards in one machine, then you can add an eth4
  entry and an eth5 entry and so on.

  Note that if you are intending to use Linux as a gateway between two
  networks, you will have to re-compile a kernel with IP forwarding
  enabled. Usually using an old AT/286 with something like the `kbridge'
  software is a better solution.

  If you are viewing this while net-surfing, you may wish to look at a
  mini-howto Donald has on his WWW site. Check out Multiple Ethercards
  <http://cesdis.gsfc.nasa.gov/linux/misc/multicard.html>.

  For module users with 8390 based cards, you can have a single module
  control multiple cards as well. Please see ``8390 Based Cards as
  Modules'' for module specific information about using multiple cards.

  3.3.  Poor NE2000 Clones

  Here is a list of some of the NE-2000 clones that are known to have
  various problems. Most of them aren't fatal. In the case of the ones
  listed as `bad clones' -- this usually indicates that the cards don't
  have the two NE2000 identifier bytes. NEx000-clones have a Station
  Address PROM (SAPROM) in the packet buffer memory space.  NE2000
  clones have 0x57,0x57 in bytes 0x0e,0x0f of the SAPROM, while other
  supposed NE2000 clones must be detected by their SA prefix.

  This is not a comprehensive list of all the NE2000 clones that don't
  have the 0x57,0x57 in bytes 0x0e,0x0f of the SAPROM. There are
  probably hundreds of them. If you get a card that causes the driver to
  report an `invalid signature' then you will have to add your cards
  signature to the driver. The process for doing this is described
  below.

  Accton NE2000 -- might not get detected at boot, see below.

  Aritsoft LANtastic AE-2 -- OK, but has flawed error-reporting
  registers.

  AT-LAN-TEC NE2000 -- clone uses Winbond chip that traps SCSI drivers

  ShineNet LCS-8634 -- clone uses Winbond chip that traps SCSI drivers

  Cabletron E10**, E20**, E10**-x, E20**-x -- bad clones, but the driver
  checks for them. See ``E10**''.

  D-Link Ethernet II -- bad clones, but the driver checks for them. See
  ``DE-100 / DE-200''.

  DFI DFINET-300, DFINET-400 -- bad clones, but the driver checks for
  them. See ``DFI-300 / DFI-400''

  EtherNext UTP8, EtherNext UTP16 -- bad clones, but the driver checks
  for them.

  3.4.  Problems with NE1000 / NE2000 cards (and clones)

  Problem: NE*000 card hangs machine, sometimes with a `DMA conflict'
  message, sometimes completely silently.

  Reason: There were some bugs in the driver and the upper networking
  layers that caused this. They have been fixed in kernels v1.2.9 and
  above. Upgrade your kernel.

  Problem: NE*000 card hangs machine during NE probe, or can not read
  station address properly.

  Reason: Kernels previous to v1.3.7 did not fully reset the card after
  finding it at boot. Some cheap cards are not left in a reasonable
  state after power-up and need to be fully reset before any attempt is
  made to use them. Also, a previous probe may have upset the NE card
  prior to the NE probe taking place. In that case, look in to using the
  ``reserve='' boot keyword to protect the card from other probes.

  Problem: NE*000 driver reports `not found (no reset ack)' during boot
  probe.

  Reason: This is related to the above change. After the initial
  verification that an 8390 is at the probed i/o address, the reset is
  performed. When the card has completed the reset, it is supposed to
  acknowedge that the reset has completed.  Your card doesn't, and so
  the driver assumes that no NE card is present.

  Solution:

  Change the two lines as shown below in drivers/net/ne.c

  ______________________________________________________________________
  -                       printk(" not found (no reset ack).\n");
  -                       return ENODEV;
  +                       printk(" (warning: no reset ack)");
  +                       break;
  ______________________________________________________________________

  This will allow the card detection to continue, even if your card
  doesn't ACK the reset.

  Problem: NE*000 card hangs machine at first network access.

  Reason: This problem has been reported for kernels as old as 1.1.57 to
  the present. It appears confined to the software configurable clone
  cards. It appears that they expect to be initialized in some special
  way.

  Solution: Several people have reported that running the supplied DOS
  software config program and/or the supplied DOS driver prior to warm
  booting (i.e. loadlin or the `three-finger-salute') into linux allowed
  the card to work. This would indicate that these cards need to be
  initialized in a particular fashion, slightly different than what the
  present Linux driver does.

  Problem: NE*000 ethercard at 0x360 doesn't get detected anymore.

  Reason: Recent kernels ( > 1.1.7X) have more sanity checks with
  respect to overlapping i/o regions. Your NE2000 card is 0x20 wide in
  i/o space, which makes it hit the parallel port at 0x378.  Other
  devices that could be there are the second floppy controller (if
  equipped) at 0x370 and the secondary IDE controller at 0x376--0x377.
  If the port(s) are already registered by another driver, the kernel
  will not let the probe happen.

  Solution: Either move your card to an address like 0x280, 0x340, 0x320
  or compile without parallel printer support.

  Problem: Network `goes away' every time I print something (NE2000)

  Reason: Same problem as above, but you have an older kernel that
  doesn't check for overlapping i/o regions. Use the same fix as above,
  and get a new kernel while you are at it.

  Problem: NE*000 ethercard probe at 0xNNN: 00 00 C5 ... not found.
  (invalid signature yy zz)

  Reason: First off, do you have a NE1000 or NE2000 card at the addr.
  0xNNN?  And if so, does the hardware address reported look like a
  valid one? If so, then you have a poor NE*000 clone. All NE*000 clones
  are supposed to have the value 0x57 in bytes 14 and 15 of the SA PROM
  on the card. Yours doesn't -- it has `yy zz' instead.

  Solution: The driver (/usr/src/linux/drivers/net/ne.c) has a "Hall of
  Shame" list at about line 42. This list is used to detect poor clones.
  For example, the DFI cards use `DFI' in the first 3 bytes of the prom,
  instead of using 0x57 in bytes 14 and 15, like they are supposed to.

  You can determine what the first 3 bytes of your card PROM are by
  adding a line like:

      printk("PROM prefix: %2.2x %2.2x %2.2x\n",SA_prom[0],SA_prom[1],SA_prom[2]);

  into the driver, right after the error message you got above, and just
  before the "return ENXIO" at line 227.

  Reboot with this change in place, and after the detection fails, you
  will get the three bytes from the PROM like the DFI example above.
  Then you can add your card to the bad_clone_list[] at about line 43.
  Say the above line printed out:

       PROM prefix: 0x3F 0x2D 0x1C

  after you rebooted. And say that the 8 bit version of your card was
  called the "FOO-1k" and the 16 bit version the "FOO-2k". Then you
  would add the following line to the bad_clone_list[]:

       {"FOO-1k", "FOO-2k", {0x3F, 0x2D, 0x1C,}},

  Note that the 2 name strings you add can be anything -- they are just
  printed at boot, and not matched against anything on the card.  You
  can also take out the "printk()" that you added above, if you want.
  It shouldn't hit that line anymore anyway. Then recompile once more,
  and your card should be detected.

  Problem: Errors like DMA address mismatch

  Is the chip a real NatSemi 8390? (DP8390, DP83901, DP83902 or
  DP83905)?  If not, some clone chips don't correctly implement the
  transfer verification register. MS-DOS drivers never do error
  checking, so it doesn't matter to them. (Note: The DMA address check
  is not done by default as of v1.2.4 for performance reasons. Enable it
  with the `NE_SANITY' define in ne.c if you want the check done.)

  Are most of the messages off by a factor of 2?  If so:  Are you using
  the NE2000 in a 16 bit slot?  Is it jumpered to use only 8 bit
  transfers?

  The Linux driver expects a NE2000 to be in a 16 bit slot. A NE1000 can
  be in either size slot. This problem can also occur with some clones,
  notably D-Link 16 bit cards, that don't have the correct ID bytes in
  the station address PROM.

  Are you running the bus faster than 8Mhz?  If you can change the speed
  (faster or slower), see if that makes a difference. Most NE2000 clones
  will run at 16MHz, but some may not. Changing speed can also mask a
  noisy bus.

  What other devices are on the bus?  If moving the devices around
  changes the reliability, then you have a bus noise problem -- just
  what that error message was designed to detect. Congratulations,
  you've probably found the source of other problems as well.

  Problem: The machine hangs during boot right after the `8390...'  or
  `WD....' message. Removing the NE2000 fixes the problem.

  Solution: Change your NE2000 base address to 0x340. Alternatively, you
  can use the device registrar implemented in 0.99pl13 and later
  kernels.

  Reason: Your NE2000 clone isn't a good enough clone. An active NE2000
  is a bottomless pit that will trap any driver autoprobing in its
  space. The other ethercard drivers take great pain to reset the NE2000
  so that it's safe, but some clones cannot be reset. Clone chips to
  watch out for: Winbond 83C901. Changing the NE2000 to a less-popular
  address will move it out of the way of other autoprobes, allowing your
  machine to boot.

  Problem: The machine hangs during the SCSI probe at boot.

  Reason: It's the same problem as above, change the ethercard's
  address, or use the device registrar.

  Problem: The machine hangs during the soundcard probe at boot.

  Reason: No, that's really during the silent SCSI probe, and it's the
  same problem as above.

  Problem: NE2000 not detected at boot - no boot messages at all

  Donald writes: `A few people have reported a problem with detecting
  the Accton NE2000.  This problem occurs only at boot-time, and the
  card is later detected at run-time by the identical code my (alpha-
  test) ne2k diagnostic program. Accton has been very responsive, but I
  still haven't tracked down what is going on. I've been unable to
  reproduce this problem with the Accton cards we purchased. If you are
  having this problem, please send me an immediate bug report. For that
  matter, if you have an Accton card send me a success report, including
  the type of the motherboard. I'm especially interested in finding out
  if this problem moves with the particular ethercard, or stays with the
  motherboard.'

  Here are some things to try, as they have fixed it for some people:

  ╖  Change the bus speed, or just move the card to a different slot.

  ╖  Change the `I/O recovery time' parameter in the BIOS chipset
     configuration.

  3.5.  Problems with WD80*3 cards

  Problem: A WD80*3 is falsely detected. Removing the sound or MIDI card
  eliminates the `detected' message.

  Reason: Some MIDI ports happen to produce the same checksum as a WD
  ethercard.

  Solution: Update your ethercard driver: new versions include an
  additional sanity check. If it is the midi chip at 0x388 that is
  getting detected as a WD living at 0x380, then you could also use:

          LILO: linux reserve=0x380,8

  Problem: You get messages such as the following with your 80*3:

          eth0: bogus packet size, status = NNNN
          kmalloc called with impossibly large argument (65400)
          eth0: Couldn't allocate sk_buff of size 65400
          eth0: receiver overrun

  Reason: There is a shared memory problem.

  Solution: If the problem is sporadic, you have hardware problems.
  Typical problems that are easy to fix are board conflicts, having
  cache or `shadow ROM' enabled for that region, or running your bus
  faster than 8Mhz. There are also a surprising number of memory
  failures on ethernet cards, so run a diagnostic program if you have
  one for your ethercard.

  If the problem is continual, and you have have to reboot to fix the
  problem, record the boot-time probe message and mail it to
  [e-mail] - Take particular note of the shared
  memory location.

  Problem: WD80*3 will not get detected at boot.

  Reason: Earlier versions of the Mitsumi CD-ROM (mcd) driver probe at
  0x300 will succeed if just about anything is that I/O location.  This
  is bad news and needs to be a bit more robust.  Once another driver
  registers that it `owns' an I/O location, other drivers (incl. the
  wd80x3) are `locked out' and can not probe that addr for a card.

  Solution: Recompile a new kernel without any excess drivers that you
  aren't using, including the above mcd driver.  Or try moving your
  ethercard to a new I/O addr. Valid I/O addr. for all the cards are
  listed in ``Probed Addresses'' You can also point the mcd driver off
  in another direction by a boot-time parameter (via LILO) such as:

       mcd=0x200,12

  Problem: Old wd8003 and/or jumper-settable wd8013 always get the IRQ
  wrong.

  Reason: The old wd8003 cards and jumper-settable wd8013 clones don't
  have the EEPROM that the driver can read the IRQ setting from.  If the
  driver can't read the IRQ, then it tries to auto-IRQ to find out what
  it is. And if auto-IRQ returns zero, then the driver just assigns IRQ
  5 for an 8 bit card or IRQ 10 for a 16 bit card.

  Solution: Avoid the auto-IRQ code, and tell the kernel what the IRQ
  that you have jumpered the card to is via a boot time argument.  For
  example, if you are using IRQ 9, using the following should work.

       LILO: linux ether=9,0,eth0

  3.6.  Problems with 3Com cards

  Problem: The 3c503 picks IRQ N, but this is needed for some other
  device which needs IRQ N. (eg. CD ROM driver, modem, etc.)  Can this
  be fixed without compiling this into the kernel?

  Solution: The 3c503 driver probes for a free IRQ line in the order {5,
  9/2, 3, 4}, and it should pick a line which isn't being used. Very old
  drivers used to pick the IRQ line at boot-time, and the current driver
  (0.99pl12 and newer) chooses when the card is open()/ifconfig'ed.
  Alternately, you can fix the IRQ at boot by passing parameters via
  LILO. The following selects IRQ9, base location 0x300, <ignored
  value>, and if_port #1 (the external transceiver).

       LILO: linux ether=9,0x300,0,1,eth0

  The following selects IRQ3, probes for the base location, <ignored
  value>, and the default if_port #0 (the internal transceiver)

       LILO: linux ether=3,0,0,0,eth0

  Problem: 3c503: configured interrupt X invalid, will use autoIRQ.

  Reason: The 3c503 card can only use one of IRQ{5, 2/9, 3, 4} (These
  are the only lines that are connected to the card.)  If you pass in an
  IRQ value that is not in the above set, you will get the above
  message.  Usually, specifying an interrupt value for the 3c503 is not
  necessary. The 3c503 will autoIRQ when it gets ifconfig'ed, and pick
  one of IRQ{5, 2/9, 3, 4}.

  Solution: Use one of the valid IRQs listed above, or enable autoIRQ by
  not specifying the IRQ line at all.

  Problem: The supplied 3c503 drivers don't use the AUI (thicknet) port.
  How does one choose it over the default thinnet port?

  Solution: The 3c503 AUI port can be selected at boot-time with
  0.99pl12 and later. The selection is overloaded onto the low bit of
  the currently-unused dev->rmem_start variable, so a boot-time
  parameter of:

       LILO: linux ether=0,0,0,1,eth0

  should work. A boot line to force IRQ 5, port base 0x300, and use an
  external transceiver is:

       LILO: linux ether=5,0x300,0,1,eth0

  With kernels 1.3.42 and newer, you can specify the AUI port when
  loading as a module as well. Just append xcvr=1 to the insmod command
  line along with your i/o and irq values.

  Also note that kernel revisions 1.00 to 1.03 had an interesting
  `feature'. They would switch to the AUI port when the internal
  transceiver failed. This is a problem, as it will never switch back if
  for example you momentarily disconnect the cable. Kernel versions 1.04
  and newer only switch if the very first Tx attempt fails.

  3.7.  Problems with Hewlett Packard Cards

  Problem: HP Vectra using built in AMD LANCE chip gets IRQ and DMA
  wrong.

  Solution: The HP Vectra uses a different implementation to the
  standard HP-J2405A. The `lance.c' driver used to always use the value
  in the setup register of an HP Lance implementation.  In the Vectra
  case it's reading an invalid 0xff value. Kernel versions newer than
  about 1.1.50 now handle the Vectra in an appropriate fashion.

  Problem: HP Card is not detected at boot, even though kernel was
  compiled with `HP PCLAN support'.

  Solution: You probably have a HP PCLAN+  -- note the `plus'. Support
  for the PCLAN+ was added to mid/late versions of 1.1.  Recompile a
  (possibly newer) kernel with support for the HP PCLAN+ and you should
  be in business.

  3.8.  FAQs Not Specific to Any Card.

  3.8.1.  Ethercard is Not Detected at Boot.

  The usual reason for this is that people are using a kernel that does
  not have support for their particular card built in. If you are using
  a pre-compiled kernel that is part of a distribution set, then check
  the documentation to see which kernel you installed, and if it was
  built with support for your particular card. If it wasn't, then your
  options are to try and get one that has support for your card, or
  build your own.

  It is usually wise to build your own kernel with only the drivers you
  need, as this cuts down on the kernel size (saving your precious RAM
  for applications!) and reduces the number of device probes that can
  upset sensitive hardware. Building a kernel is not as complicated as
  it sounds. You just have to answer yes or no to a bunch of questions
  about what drivers you want, and it does the rest.

  The next main cause is having another device using part of the i/o
  space that your card needs. Most cards are 16 or 32 bytes wide in i/o
  space. If your card is set at 0x300 and 32 bytes wide, then the driver
  will ask for 0x300-0x31f. If any other device driver has registered
  even one port anywhere in that range, the probe will not take place at
  that address and  the driver will silently continue to the next of the
  probed addresses. So, after booting, do a cat /proc/ioports and verify
  that the full iospace that the card will require is vacant.

  Another problem is having your card jumpered to an i/o address that
  isn't probed by default. There is a list ``probed addresses'' for each
  card in this document. Even if the i/o setting of your card is not in
  the list of porbed addresses, you can supply it at boot with the
  ether= command as described in ``Passing Ethernet Arguments...''

  3.8.2.  ifconfig reports the wrong i/o address for the card.

  No it doesn't. You are just interpreting it incorrectly.  This is not
  a bug, and the numbers reported are correct. It just happens that some
  8390 based cards (wd80x3, smc-ultra, etc) have the actual 8390 chip
  living at an offset from the first assigned i/o port.  Try cd
  /usr/src/linux/drivers/net;grep NIC_OFFSET *.c|more to see what is
  going on. This is the value stored in dev->base_addr, and is what
  ifconfig reports. If you want to see the full range of ports that your
  card uses, then try cat /proc/ioports which will give the numbers you
  expect.

  3.8.3.  Shared Memory ISA cards in PCI Machine

  This will usually show up as reads of lots of 0xffff values.  No
  shared memory cards of any type will work in a PCI machine unless you
  have the PCI ROM BIOS/CMOS SETUP configuration set properly. You have
  to set it to allow shared memory access from the ISA bus for the
  memory region that your card is trying to use. If you can't figure out
  which settings are applicable then ask your supplier or local computer
  guru.

  3.8.4.  Asynchronous Transfer Mode (ATM) Support

  Werner Almesberger has been playing around with ATM support for linux.
  He has been working with the Efficient Networks ENI155p board
  (Efficient Networks <http://www.efficient.com/>) and the Zeitnet
  ZN1221 board (Zeitnet <http://www.zeitnet.com/>).

  Werner says that the driver for the ENI155p is rather stable, while
  the driver for the ZN1221 is presently unfinished.

  Check the latest/updated status at the following URL:

  Linux ATM Support <http://lrcwww.epfl.ch/linux-atm/>

  3.8.5.  FDDI Support

  Is there FDDI support for Linux?

  Donald writes: `No, there is no Linux driver for any FDDI boards.  I
  come from a place with supercomputers, so an external observer might
  think FDDI would be high on my list. But FDDI never delivered end-to-
  end throughput that would justify its cost, and it seems to be a
  nearly abandoned technology now that 100base{X,Anynet} seems imminent.
  (And yes, I know you can now get FDDI boards for <$1K. That seems to
  be a last-ditch effort to get some return on the development
  investment. Where is the next generation of FDDI going to come from?)'

  3.8.6.  Ethernet Cards for Linux on Alpha/AXP PCI Boards

  At present only the depca, de4x5 and all the 8390 drivers (wd, smc-
  ultra, ne, 3c503, e2100, ac3200, hp, hp-plus) have been made
  `architecture independent' so as to work on the DEC Alpha CPU based
  systems.

  Note that the changes that are required aren't that complicated.  You
  only need to do the following:

  -multiply all jiffies related values by HZ/100 to account for the
  different HZ value that the Alpha uses.  (i.e timeout=2; becomes
  timeout=2*HZ/100;)

  -replace any i/o memory (640k to 1MB) pointer dereferences with the
  appropriate readb() writeb() readl() writel() calls, as shown in this
  example.

  ______________________________________________________________________
  -       int *mem_base = (int *)dev->mem_start;
  -       mem_base[0] = 0xba5eba5e;
  +       unsigned long mem_base = dev->mem_start;
  +       writel(0xba5eba5e, mem_base);
  ______________________________________________________________________

  -replace all memcpy() calls that have i/o memory as source or target
  destinations with the appropriate one of memcpy_fromio() or
  memcpy_toio().

  3.8.7.  Linking 10BaseT without a Hub

  Can I link 10BaseT (RJ45) based systems together without a hub?

  You can link 2 machines easily, but no more than that, without extra
  devices/gizmos. See ``Twisted Pair'' -- it explains how to do it. And
  no, you can't hack together a hub just by crossing a few wires and
  stuff. It's pretty much impossible to do the collision signal right
  without duplicating a hub.

  3.8.8.  SIOCSIFxxx: No such device

  I get a bunch of `SIOCSIFxxx: No such device' messages at boot,
  followed by a `SIOCADDRT: Network is unreachable' What is wrong?

  Your ethernet device was not detected at boot, and when ifconfig and
  route are run, they have no device to work with. Use dmesg | more to
  review the boot messages and see if there are any messages about
  detecting an ethernet card.

  3.8.9.  SIOCSFFLAGS: Try again

  I get `SIOCSFFLAGS: Try again' when I run `ifconfig' -- Huh?

  Some other device has taken the IRQ that your ethercard is trying to
  use, and so the ethercard can't use the IRQ.  You don't necessairly
  need to reboot to resolve this, as some devices only grab the IRQs
  when they need them and then release them when they are done. Examples
  are some sound cards, serial ports, floppy disk driver, etc. You can
  type cat /proc/interrupts to see which interrupts are presently in
  use. Most of the Linux ethercard drivers only grab the IRQ when they
  are opened for use via `ifconfig'. If you can get the other device to
  `let go' of the required IRQ line, then you should be able to `Try
  again' with ifconfig.

  3.8.10.  Link UNSPEC and HW-addr of 00:00:00:00:00:00

  When I run ifconfig with no arguments, it reports that LINK is UNSPEC
  (instead of 10Mbs Ethernet) and it also says that my hardware address
  is all zeros.

  This is because people are running a newer version of the `ifconfig'
  program than their kernel version. This new version of ifconfig is not
  able to report these properties when used in conjunction with an older
  kernel. You can either upgrade your kernel, `downgrade' ifconfig, or
  simply ignore it. The kernel knows your hardware address, so it really
  doesn't matter if ifconfig can't read it.

  3.8.11.  Huge Number of RX and TX Errors

  When I run ifconfig with no arguments, it reports that I have a huge
  error count in both rec'd and transmitted packets. It all seems to
  work ok -- What is wrong?

  Look again. It says RX packets big number PAUSE errors 0 PAUSE dropped
  0 PAUSE overrun 0.  And the same for the TX column.  Hence the big
  numbers you are seeing are the total number of packets that your
  machine has rec'd and transmitted.  If you still find it confusing,
  try typing cat /proc/net/dev instead.

  3.8.12.  Entries in /dev/ for Ethercards

  I have /dev/eth0 as a link to /dev/xxx. Is this right?

  Contrary to what you have heard, the files in /dev/* are not used.
  You can delete any /dev/wd0, /dev/ne0 and similar entries.

  3.8.13.  Linux and ``trailers''

  Should I disable trailers when I `ifconfig' my ethercard?

  You can't disable trailers, and you shouldn't want to. `Trailers' are
  a hack to avoid data copying in the networking layers. The idea was to
  use a trivial fixed-size header of size `H', put the variable-size
  header info at the end of the packet, and allocate all packets `H'
  bytes before the start of a page. While it was a good idea, it turned
  out to not work well in practice.  If someone suggests the use of
  `-trailers', note that it is the equivalent of sacrificial goats
  blood. It won't do anything to solve the problem, but if problem fixes
  itself then someone can claim deep magical knowledge.

  3.8.14.  Access to the raw Ethernet Device

  How do I get access to the raw ethernet device in linux, without going
  through TCP/IP and friends?

  ______________________________________________________________________
          int s=socket(AF_INET,SOCK_PACKET,htons(ETH_P_ALL));
  ______________________________________________________________________

  This gives you a socket receiving every protocol type.  Do recvfrom()
  calls to it and it will fill the sockaddr with device type in
  sa_family and the device name in the sa_data array. I don't know who
  originally invented SOCK_PACKET for Linux (its been in for ages) but
  its superb stuff.  You can use it to send stuff raw too via sendto()
  calls.  You have to have root access to do either of course.

  4.  Performance Tips

  Here are some tips that you can use if you are suffering from low
  ethernet throughput, or to gain a bit more speed on those ftp
  transfers.

  The ttcp.c program is a good test for measuring raw throughput speed.
  Another common trick is to do a ftp> get large_file /dev/null where
  large_file is > 1MB and residing in the buffer cache on the Tx'ing
  machine. (Do the `get' at least twice, as the first time will be
  priming the buffer cache on the Tx'ing machine.) You want the file in
  the buffer cache because you are not interested in combining the file
  access speed from the disk into your measurement. Which is also why
  you send the incoming data to /dev/null instead of onto the disk.

  4.1.  General Concepts

  Even an 8 bit card is able to receive back-to-back packets without any
  problems. The difficulty arises when the computer doesn't get the Rx'd
  packets off the card quick enough to make room for more incoming
  packets. If the computer does not quickly clear the card's memory of
  the packets already received, the card will have no place to put the
  new packet.

  In this case the card either drops the new packet, or writes over top
  of a previously received packet. Either one seriously interrupts the
  smooth flow of traffic by causing/requesting re-transmissions and can
  seriously degrade performance by up to a factor of 5!

  Cards with more onboard memory are able to ``buffer'' more packets,
  and thus can handle larger bursts of back-to-back packets without
  dropping packets.  This in turn means that the card does not require
  as low a latency from the the host computer with respect to pulling
  the packets out of the buffer to avoid dropping packets.

  Most 8 bit cards have an 8kB buffer, and most 16 bit cards have a 16kB
  buffer. Most Linux drivers will reserve 3kB of that buffer (for two Tx
  ping-pong buffers), leaving only 5kB of receive space for an 8 bit
  card. This is room enough for only three full sized (1500 bytes)
  ethernet packets.

  4.2.  ISA Bus Speed

  As mentioned above, if the packets are removed from the card fast
  enough, then a drop/overrun condition won't occur even when the amount
  of Rx packet buffer memory is small. The factor that sets the rate at
  which packets are removed from the card to the computer's memory is
  the speed of the data path that joins the two -- that being the ISA
  bus speed. (If the CPU is a dog-slow 386sx-16, then this will also
  play a role.)

  The recommended ISA bus clock is about 8MHz, but many motherboards and
  peripheral devices can run at higher frequencies. The clock frequency
  for the ISA bus can usually be set in the CMOS setup, by selecting a
  divisor of the mainboard/CPU clock frequency.

  For example, here are some receive speeds as measured by the TTCP
  program on a 40MHz 486, with an old 8 bit WD8003EP card, for different
  ISA bus speeds.

  ______________________________________________________________________
          ISA Bus Speed (MHz)     Rx TTCP (kB/s)
          -------------------     --------------
          6.7                     740
          13.4                    970
          20.0                    1030
          26.7                    1075
  ______________________________________________________________________

  You would be hard pressed to do better than 1075kB/s with any 10Mb/s
  ethernet card, using TCP/IP. However, don't expect every system to
  work at fast ISA bus speeds. Most systems will not function properly
  at speeds above 13MHz. (Also, most PCI systems have the ISA bus speed
  fixed at 8MHz, so that the end user does not have the option of
  increasing it.)

  In addition to faster transfer speeds, one will usually also benefit
  from a reduction in CPU usage due to the shorter duration memory and
  i/o cycles. (Note that hard disks and video cards located on the ISA
  bus will also usually experience a performance increase from an
  increased ISA bus speed.)

  4.3.  Setting the TCP Rx Window

  Once again, cards with small amounts of onboard RAM and relatively
  slow data paths between the card and the computer's memory run into
  trouble. The default TCP Rx window setting is 32kB, which means that a
  fast computer on the same subnet as you can dump 32k of data on you
  without stopping to see if you received any of it okay.

  Recent versions of the route command have the ability to set the size
  of this window on the fly. Usually it is only for the local net that
  this window must be reduced, as computers that are behind a couple of
  routers or gateways are `buffered' enough to not pose a problem. An
  example usage would be:

  ______________________________________________________________________
          route add <whatever> ... window <win_size>
  ______________________________________________________________________

  where win_size is the size of the window you wish to use (in bytes).
  An 8 bit 3c503 card on an ISA bus operating at a speed of 10MHz or
  less would work well with a window size of about 4kB. Too large a
  window will cause overruns and dropped packets, and a drastic
  reduction in ethernet throughput. You can check the operating status
  by doing a cat /proc/net/dev which will display any dropped or overrun
  conditions that occurred.

  4.4.  Increasing NFS performance

  Some people have found that using 8 bit cards in NFS clients causes
  poorer than expected performance, when using 8kB (native Sun) NFS
  packet size.

  The possible reason for this could be due to the difference in on
  board buffer size between the 8 bit and the 16 bit cards.  The maximum
  ethernet packet size is about 1500 bytes. Now that 8kB NFS packet will
  arrive as about 6 back to back maximum size ethernet packets. Both the
  8 and 16 bit cards have no problem Rx'ing back to back packets. The
  problem arises when the machine doesn't remove the packets from the
  cards buffer in time, and the buffer overflows. The fact that 8 bit
  cards take an extra ISA bus cycle per transfer doesn't help either.
  What you can do if you have an 8 bit card is either set the NFS
  transfer size to 4kB, or try increasing the ISA bus speed in order to
  get the card's buffer cleared out faster.

  5.  Vendor/Manufacturer/Model Specific Information

  5.1.  3Com

  If you are not sure what your card is, but you think it is a 3Com
  card, you can probably figure it out from the assembly number. 3Com
  has a document `Identifying 3Com Adapters By Assembly Number' (ref
  24500002) that would most likely clear things up. See ``Technical
  Information from 3Com'' for info on how to get documents from 3Com.

  Also note that 3Com has a FTP site with various goodies: ftp.3Com.com
  that you may want to check out.

  For those of you browsing this document by a WWW browser, you can try
  3Com's WWW site

  5.1.1.  3c501

  Status -- Semi-Supported

  Too brain-damaged to use. Available surplus from many places. Avoid it
  like the plague. Again, do not purchase this card, even as a joke.
  It's performance is horrible, and it breaks in many ways.

  Cameron L. Spitzer of 3Com said: ``I'm speaking only for myself here,
  of course, but I believe 3Com advises against installing a 3C501 in a
  new system, mostly for the same reasons Donald has discussed. You
  probably won't be happy with the 3C501 in your Linux box. The data
  sheet is marked `(obsolete)' on 3Com's Developers' Order Form, and the
  board is not part of 3Com's program for sending free Technical
  Reference Manuals to people who need them. The decade-old things are
  nearly indestructible, but that's about all they've got going for them
  any more.''

  For those not yet convinced, the 3c501 can only do one thing at a time
  -- while you are removing one packet from the single-packet buffer it
  cannot receive another packet, nor can it receive a packet while
  loading a transmit packet. This was fine for a network between two
  8088-based computers where processing each packet and replying took
  10's of msecs, but modern networks send back-to-back packets for
  almost every transaction.

  AutoIRQ works, DMA isn't used, the autoprobe only looks at 0x280 and
  0x300, and the debug level is set with the third boot-time argument.

  Once again, the use of a 3c501 is strongly discouraged!  Even more so
  with a IP multicast kernel, as you will grind to a halt while
  listening to all multicast packets. See the comments at the top of the
  source code for more details.

  5.1.2.  3c503, 3c503/16

  Status -- Supported

  If you have a 3c503/16 you may be interested to know that as of 1.3.37
  the driver has the facility to use the full 16kB RAM on your card.
  Previous versions treated the 16bit cards as 8bit cards, and only used
  half of the available RAM. This update also detects the newer 3Com
  prefix found on newly manufactured cards mentioned below.

  Recently made 3c503/16 cards have a new base hardware address because
  3Com ran out of numbers (they made too many cards!) The cards used to
  start with 02 60 8C and the newer ones use 00 20 AF. Up to 1.3.37, the
  driver will only check for the old address, and skip over the newer
  cards.  You can upgrade to a kernel newer than 1.3.37, or change the
  numbers in 3c503.c for older kernels.

  These shared-memory ethercards also have a programmed I/O mode that
  doesn't use the 8390 facilities (their engineers found too many bugs!)
  It should be about the same speed as the same bus width WD80x3, but it
  is actually a bit slower.  The 3c503 does not have ``EEPROM setup'',
  so a diagnostic/setup program isn't needed before running the card
  with Linux. The shared memory address of the 3c503 is set using
  jumpers that are shared with the boot PROM address. This is confusing
  to people familiar with other ISA cards, where you always leave the
  jumper set to ``disable'' unless you have a boot PROM.

  The Linux 3c503 driver can also work with the 3c503 in programmed-I/O
  mode, but this is slower and less reliable than shared memory mode.
  Also, programmed-I/O mode is not as well tested when updating the
  drivers.  You still shouldn't use the programmed-I/O mode though,
  unless you need it for MS-DOS compatibility.

  The 3c503's IRQ line is set in software, with no hints from an EEPROM.
  Unlike the MS-DOS drivers, the Linux driver has capability to autoIRQ:
  it uses the first available IRQ line in {5,2/9,3,4}, selected each
  time the card is ifconfig'ed. (Older driver versions selected the IRQ
  at boot time.) The ioctl() call in `ifconfig' will return EAGAIN if no
  IRQ line is available at that time.

  Some common problems that people have with the 503 are discussed in
  ``Problems with...''.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.1.3.  3c505

  Status -- Semi-Supported

  This is a driver that was written by Craig Southeren
  [e-mail]. These cards also use the i82586 chip.
  There are not that many of these cards about.  It is included in the
  standard kernel, but it is classed as an alpha driver. See ``Alpha
  Drivers'' for important information on using alpha-test ethernet
  drivers with Linux.

  There is also the file /usr/src/linux/drivers/net/README.3c505 that
  you should read if you are going to use one of these cards.  It
  contains various options that you can enable/disable.  Technical
  information is available in ``Programming the Intel chips''.

  5.1.4.  3c507

  Status -- Semi-Supported

  This card uses one of the Intel chips, and the development of the
  driver is closely related to the development of the Intel Ether
  Express driver.  The driver is included in the standard kernel
  release, but as an alpha driver.

  See ``Alpha Drivers'' for important information on using alpha-test
  ethernet drivers with Linux. Technical information is available in
  ``Programming the Intel chips''.

  5.1.5.  3c509 / 3c509B

  Status -- Supported

  Note: Donald has an updated driver for these cards that is not
  presently in the default kernel. It fixes harmless irq N for unknown
  device messages at boot, has better handling for the 3c509B Plug and
  Pray cards, and recovers from certain adapter failure status values.

  It's fairly inexpensive and has excellent performance for a non-bus-
  master design.  The drawbacks are that the original 3c509 requires
  very low interrupt latency. The 3c509B shouldn't suffer from the same
  problem, due to having a larger buffer. (See below.)

  Note that the ISA card detection uses a different method than most
  cards. Basically, you ask the cards to respond by sending data to an
  ID_PORT (port 0x100). Note that if you have some other strange ISA
  card using an I/O range that includes the ID_PORT of the 3c509, it
  will probably not get detected. Note that you can change the ID_PORT
  to 0x110 or 0x120 or... in 3c509.c if you have a conflicting ISA card,
  and the 3c509 will still be happy.  Also note that this detection
  method means that a particular card will always get detected first in
  a multiple ISA 3c509 configuration.  The card with the lowest hardware
  ethernet address will always end up being eth0. This shouldn't matter
  to anyone, except for those people who want to assign a 6 byte
  hardware address to a particular interface.  If you have multiple
  3c509 cards, it is best to append ether=0,0,ethN commands without the
  i/o port specified (i.e. use i/o=zero) and allow the probe to sort out
  which card is first, otherwise it may not detect all your cards.

  The original 3c509 has a smaller packet buffer (4kB total, 2kB Rx, 2kB
  Tx), causing the driver to occasionally drop a packet if interrupts
  are masked for too long. To minimize this problem, you can try
  unmasking interrupts during IDE disk transfers (see hdparm(8)) and/or
  increasing your ISA bus speed so IDE transfers finish sooner.

  (Note that the driver could be completely rewritten to use predictive
  interrupts, but performance re-writes of working drivers are low
  priority unless there is some particular incentive or need.)

  Cameron Spitzer writes: ``Beware that if you put a '509 in EISA
  addressing mode by mistake and save that in the EEPROM, you'll have to
  use an EISA machine or the infamous Test Via to get it back to normal,
  and it will conflict at IO location 0 which may hang your ISA machine.
  I believe this problem is corrected in the 3C509B version of the
  board.''

  The newer model 3c509B has 8kB on board, and the buffer can be split
  4/4, 5/3 or 6/2 for Rx/Tx. This setting can also be stored on the
  EEPROM. This should alleviate the above problem with the original
  3c509. At this point in time, the Linux driver is not aware of this,
  and treats the 3c509B as an older 3c509.

  3c509B users should use the supplied DOS utility to disable the plug
  and play support, and to set the output media to what they require.
  Cameron adds: ``The 3C509B has 3Com's relocatable I/O port scheme, and
  Microsofttm Plug-and-play ("PnP").  You can't use them both at the
  same time.  Some (broken, IMHO) BIOSes begin a PnP sequence by writing
  to the PnP address (0x279 ?), which causes PnP adapters like 3C509B to
  enter the PnP state, but then they (these funny BIOSes) never come
  back to finish the job.  The 3C509Bs hang there in the middle of the
  PnP ID Sequence, where they have no idea you didn't mean it and you're
  going to use the 3Com ID sequence after all.  3C5X9CFG /PNPRST clears
  this hang.  Disable PnP if your drivers (eg., Linux) don't use it.

  It was a marketing decision to turn PnP on as a factory default
  setting.  If it caused you a hassle, or not, please take the time to
  say so when you mail in your warranty card.  The more info they have,
  the better decisions they can make.  Also, check with your motherboard
  supplier to see if you need a BIOS upgrade.''

  With regards to the media detection features, Cameron said:
  ``Autoselect is a feature of the commercial *drivers* for 3C509(B).
  AFAIK nobody ever claimed the Linux driver attempts it.  When
  drivers/net/3c509.c recognizes my 3C509B at boot time, it says: eth0:
  3c509 at 0x300 tag 1, 10baseT port, ...  revealing that the card is
  configured for 10BASE-T.  It finds that out by reading the little
  EEPROM, which IMHO is the Right Way To Do It.''

  5.1.6.  3c523

  Status -- Not Supported

  This MCA bus card uses the i82586, and now that people are actually
  running Linux on MCA machines, someone may wish to try and recycle
  parts of the 3c507 driver into a driver for this card.

  5.1.7.  3c527

  Status -- Not Supported

  Yes, another MCA card. No, not too much interest in it.  Better
  chances with the 3c523 or the 3c529.

  5.1.8.  3c529

  Status -- Not Supported

  This card actually uses the same chipset as the 3c509.  Donald
  actually put hooks into the 3c509 driver to check for MCA cards after
  probing for EISA cards, and before probing for ISA cards. But it
  hasn't evolved much further than that. Donald writes:

  ``I don't have access to a MCA machine (nor do I fully understand the
  probing code) so I never wrote the mca_adaptor_select_mode() or
  mca_adaptor_id() routines. If you can find a way to get the adaptor
  I/O address that assigned at boot time, you can just hard-wire that in
  place of the commented-out probe. Be sure to keep the code that reads
  the IRQ, if_port, and ethernet address.''

  5.1.9.  3c562

  Status -- Supported

  This PCMCIA card is the combination of a 3c589B ethernet card with a
  modem. The modem appears as a standard modem to the end user. The only
  difficulty is getting the two separate linux drivers to share one
  interrupt. There are a couple of new registers and some hardware
  interrupt sharing support.

  Thanks again to Cameron for getting a sample unit and documentation
  sent off to David Hinds. Look for support in David's next PCMCIA
  package release.

  5.1.10.  3c579

  Status -- Supported

  The EISA version of the 509. The current EISA version uses the same 16
  bit wide chip rather than a 32 bit interface, so the performance
  increase isn't stunning.  The EISA probe code was added to 3c509.c for
  0.99pl14.  We would be interested in hearing progress reports from any
  3c579 users. (Read the above 3c509 section for info on the driver.)

  Cameron Spitzer writes: ``The 3C579 (Etherlink III EISA) should be
  configured as an EISA card. The IO Base Address (window 0 register 6
  bits 4:0) should be 1f, which selects EISA addressing mode. Logic
  outside the ASIC decodes the IO address s000, where s is the slot
  number. I don't think it was documented real well. Except for its IO
  Base Address, the '579 should behave EXACTLY like the'509 (EL3 ISA),
  and if it doesn't, I want to hear about it (at my work address).''

  5.1.11.  3c589 / 3c589B

  Status -- Semi-Supported

  Many people have been using this PCMCIA card for quite some time now.
  Note that support for it is not (at present) included in the default
  kernel source tree. You will also need a supported PCMCIA controller
  chipset. There are drivers available on Donald's ftp site:

          cesdis.gsfc.nasa.gov:/pub/linux/pcmcia/README.3c589
          cesdis.gsfc.nasa.gov:/pub/linux/pcmcia/3c589.c
          cesdis.gsfc.nasa.gov:/pub/linux/pcmcia/dbether.c

  Or for those that are net-surfing you can try:

  Don's PCMCIA Stuff <http://cesdis.gsfc.nasa.gov/linux/pcmcia.html>

  You will still need a PCMCIA socket enabler as well.

  See ``PCMCIA Support'' for more info on PCMCIA chipsets, socket
  enablers, etc.

  The "B" in the name means the same here as it does for the 3c509 case.

  5.1.12.  3c590 / 3c595

  Status -- Supported

  These ``Vortex'' cards are for PCI bus machines, with the '590 being
  10Mbps and the '595 being 3Com's 100Mbs offering.  Also note that you
  can run the '595 as a '590 (i.e. in a 10Mbps mode).  The driver will
  eventually appear in the 1.3.x kernel, but you can get the driver now
  from the following URL:

  Vortex <http://cesdis.gsfc.nasa.gov/linux/drivers/vortex.html>

  3Com has been offering an evaluation deal where you get 2 '595 cards
  for a total price of $250. Check with your local 3Com distributor to
  see if this is still available.

  A thanks to Cameron Spitzer and Terry Murphy of 3Com for sending cards
  and documentation to Donald so he could write the driver.

  5.1.13.  3c597

  Status -- Supported

  This is the recently released EISA version of the 3c59x series of
  cards. The 3c597 (aka Demon) should work with the vortex driver
  discussed above.

  5.2.  Accton

  5.2.1.  Accton MPX

  Status -- Supported

  Don't let the name fool you. This is still supposed to be a NE2000
  compatible card. The MPX is supposed to stand for MultiPacket
  Accelerator, which, according to Accton, increases throughput
  substantially. But if you are already sending back-to-back packets,
  how can you get any faster...

  5.2.2.  Accton EN1203, EN 1207, EtherDuo-PCI

  Status -- Supported

  This is another implementation of the DEC 21040 PCI chip.

  See ``DEC 21040'' for more information on these cards, and the present
  driver situation.

  5.2.3.  Accton EN2212 PCMCIA Card

  Status -- Semi-Supported

  David Hinds has been working on a driver for this card, and you are
  best to check the latest release of his PCMCIA package to see what the
  present status is.

  5.3.  Allied Telesyn/Telesis

  5.3.1.  AT1500

  Status --Supported

  These are a series of low-cost ethercards using the 79C960 version of
  the AMD LANCE. These are bus-master cards, and hence one of the faster
  ISA bus ethercards available.

  DMA selection and chip numbering information can be found in ``AMD
  LANCE''.

  More technical information on AMD LANCE based Ethernet cards can be
  found in ``Notes on AMD...''.

  5.3.2.  AT1700

  Status -- Supported

  The Allied Telesis AT1700 series ethercards are based on the Fujitsu
  MB86965. This chip uses a programmed I/O interface, and a pair of
  fixed-size transmit buffers. This allows small groups of packets to be
  sent back-to-back, with a short pause while switching buffers.

  A unique feature is the ability to drive 150ohm STP (Shielded Twisted
  Pair) cable commonly installed for Token Ring, in addition to 10baseT
  100ohm UTP (unshielded twisted pair).

  The Fujitsu chip used on the AT1700 has a design flaw: it can only be
  fully reset by doing a power cycle of the machine.  Pressing the reset
  button doesn't reset the bus interface. This wouldn't be so bad,
  except that it can only be reliably detected when it has been freshly
  reset. The solution/work-around is to power-cycle the machine if the
  kernel has a problem detecting the AT1700.

  Some production runs of the AT1700 had another problem: they are
  permanently wired to DMA channel 5.  This is undocumented, there are
  no jumpers to disable the "feature", and no driver dares use the DMA
  capability because of compatibility problems. No device driver will be
  written using DMA if installing a second card into the machine breaks
  both, and the only way to disable the DMA is with a knife.

  The at1700 driver is included in the standard kernel source tree.

  5.3.3.  AT2450

  Status -- Supported

  This is the PCI version of the AT1500, and it doesn't suffer from the
  problems that the Boca 79c970 PCI card does.  Allied Telsyn was still
  `beta testing' the card in early/mid 1995, so it may not have spread
  to various retailers yet (but it doesn't hurt to ask.)

  DMA selection and chip numbering information can be found in ``AMD
  LANCE''.

  More technical information on AMD LANCE based Ethernet cards can be
  found in ``Notes on AMD...''.

  5.4.  AMD / Advanced Micro Devices

  5.4.1.  AMD LANCE (7990, 79C960, PCnet-ISA)

  Status -- Supported

  There really is no AMD ethernet card. You are probably reading this
  because the only markings you could find on your card said AMD and the
  above number. The 7990 is the original `LANCE' chip, but most stuff
  (including this document) refer to all these similar chips as `LANCE'
  chips. (...incorrectly, I might add.)

  These above numbers refer to chips from AMD that are the heart of many
  ethernet cards.  For example, the Allied Telesis AT1500 (see
  ``AT1500'') the NE1500/2100 (see ``NE1500'') and the Boca-VLB/PCI
  cards (see ``Boca-VLB/PCI'')

  The 79C960 (a.k.a. PCnet-ISA) contains enhancements and bug fixes over
  the original 7990 LANCE design.

  One common problem people have is the `busmaster arbitration failure'
  message. This is printed out when the LANCE driver can't get access to
  the bus after a reasonable amount of time has elapsed (50us). This
  usually indicates that the motherboard implementation of bus-mastering
  DMA is broken, or some other device is hogging the bus, or there is a
  DMA channel conflict. If your BIOS setup has the `GAT option' (for
  Guaranteed Access Time) then try toggling/altering that setting to see
  if it helps.

  Chances are that the existing LANCE driver will work with all AMD
  LANCE based cards. (except perhaps some of the original 7990 designs
  with shared memory.)  This driver should also work with NE1500 and
  NE2100 clones.

  For the ISA bus master mode all structures used directly by the LANCE,
  the initialization block, Rx and Tx rings, and data buffers, must be
  accessible from the ISA bus, i.e. in the lower 16M of real memory.  If
  more than 16MB of memory is installed, low-memory `bounce-buffers' are
  used when needed.

  The DMA channel can be set with the low bits of the otherwise-unused
  dev->mem_start value (a.k.a. PARAM_1).  (see ``PARAM_1'') If unset it
  is probed for by enabling each free DMA channel in turn and checking
  if initialization succeeds.

  The HP-J2405A board is an exception: with this board it's easy to read
  the EEPROM-set values for the IRQ, and DMA.

  See ``Notes on AMD...''  for more info on these chips.

  5.4.2.  AMD 79C961 (PCnet-ISA+)

  Status -- Supported

  This is the PCnet-ISA+  -- an enhanced version of the 79C960.  It has
  support for jumper-less configuration and Plug and Play.  See the info
  in the above section.

  5.4.3.  AMD 79C965 (PCnet-32)

  Status -- Supported

  This is the PCnet-32 -- a 32 bit bus-master version of the original
  LANCE chip for VL-bus and local bus systems.  Minor cleanups were
  added to the original lance driver around v1.1.50 to support these 32
  bit versions of the LANCE chip.  The main problem was that the current
  versions of the '965 and '970 chips have a minor bug.  They clear the
  Rx buffer length field in the Rx ring when they are explicitly
  documented not to. Again, see the above info.

  5.4.4.  AMD 79C970 (PCnet-PCI)

  Status -- Supported

  This is the PCnet-PCI -- similar to the PCnet-32, but designed for PCI
  bus based systems. Again, see the above info.  Donald has modified the
  LANCE driver to use the PCI BIOS structure that was introduced by Drew
  Eckhardt for the PCI-NCR SCSI driver. This means that you need to
  build a kernel with PCI BIOS support enabled.

  Note that the Boca implementation of the 79C970 fails on fast Pentium
  machines. This is a hardware problem, as it affects DOS users as well.
  See the Boca section for more details.

  5.4.5.  AMD 79C974 (PCnet-SCSI)

  Status -- Supported

  This is the PCnet-SCSI --  which is basically treated like a '970 from
  an Ethernet point of view. A minor '974 specific fix was added to the
  1.1.8x kernels, so get a 1.1.90 or newer kernel. Also see the above
  info. Don't ask if the SCSI half of the chip is supported -- this is
  the Ethernet-Howto, not the SCSI-Howto.

  5.5.  Ansel Communications

  5.5.1.  AC3200 EISA

  Status -- Semi-Supported

  This driver is included in the present kernel as an alpha test driver.
  It is based on the common NS8390 chip used in the ne2000 and wd80x3
  cards.  Please see ``Alpha Drivers'' in this document for important
  information regarding alpha drivers.  If you use it, let Donald know
  how things work out, as not too many people have this card and
  feedback has been low, even though the driver has been in the kernel
  since v1.1.25.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.6.  Apricot

  5.6.1.  Apricot Xen-II On Board Ethernet

  Status -- Supported

  This on board ethernet uses an i82596 bus-master chip.  It can only be
  at i/o address 0x300. The author of this driver is Mark Evans. By
  looking at the driver source, it appears that the IRQ is hardwired to
  10.

  Earlier versions of the driver had a tendency to think that anything
  living at 0x300 was an apricot NIC.  Since then the hardware address
  is checked to avoid these false detections.

  5.7.  Arcnet

  Status -- Supported

  With the very low cost and better performance of ethernet, chances are
  that most places will be giving away their Arcnet hardware for free,
  resulting in a lot of home systems with Arcnet.

  An advantage of Arcnet is that all of the cards have identical
  interfaces, so one driver will work for everyone. It also has built in
  error handling so that it supposedly never loses a packet.  (Great for
  UDP traffic!)

  Avery Pennarun's arcnet driver has been in the default kernel sources
  since 1.1.80. The arcnet driver uses `arc0' as its name instead of the
  usual `eth0' for ethernet devices.  Bug reports and success stories
  can be mailed to:

  [e-mail]

  There are information files contained in the standard kernel for
  setting jumpers and general hints.

  Supposedly the driver also works with the 100Mbs ARCnet cards as well!

  5.8.  AT&T

  Note that AT&T's StarLAN is an orphaned technology, like SynOptics
  LattisNet, and can't be used in a standard 10Base-T environment,
  without a hub that `speaks' both.

  5.8.1.  AT&T T7231 (LanPACER+)

  Status -- Not Supported

  These StarLAN cards use an interface similar to the i82586 chip. At
  one point, Matthijs Melchior ([e-mail]) was playing
  with the 3c507 driver, and almost had something useable working.
  Haven't heard much since that.

  5.9.  AT-Lan-Tec / RealTek

  5.9.1.  AT-Lan-Tec / RealTek Pocket adaptor

  Status -- Supported

  This is a generic, low-cost OEM pocket adaptor being sold by AT-Lan-
  Tec, and (likely) a number of other suppliers. A driver for it is
  included in the standard kernel.  Note that there is substantial
  information contained in the driver source file `atp.c'.  BTW, the
  adaptor (AEP-100L) has both 10baseT and BNC connections!  You can
  reach AT-Lan-Tec at 1-301-948-7070. Ask for the model that works with
  Linux, or ask for tech support.

  In the Netherlands a compatible adaptor is sold under the name SHI-TEC
  PE-NET/CT, and sells for about $125. The vendor was Megasellers.  They
  state that they do not sell to private persons, but this doesn't
  appear to be strictly adhered to.  They are: Megasellers, Vianen, The
  Netherlands. They always advertise in Dutch computer magazines.  Note
  that the newer model EPP-NET/CT appears to be significantly different
  than the PE-NET/CT, and will not work with the present driver.
  Hopefully someone will come up with the programming information and
  this will be fixed up.

  In Germany, a similar adaptor comes as a no-brand-name product. Prolan
  890b, no brand on the casing, only a roman II. Resellers can get a
  price of about $130, including a small wall transformer for the power.

  The adaptor is `normal size' for the product class, about 57mm wide,
  22mm high tapering to 15mm high at the DB25 connector, and 105mm long
  (120mm including the BNC socket). It's switchable between the RJ45 and
  BNC jacks with a small slide switch positioned between the two: a very
  intuitive design.

  Donald performed some power draw measurements, and determined that the
  average current draw was only about 100mA @ 5V.  This power draw is
  low enough that you could buy or build a cable to take the 5V directly
  from the keyboard/mouse port available on many laptops. (Bonus points
  here for using a standardized power connector instead of a proprietary
  one.)

  Note that the device name that you pass to ifconfig is not eth0 but
  atp0 for this device.

  5.10.  Boca Research

  Yes, they make more than just multi-port serial cards.  :-)

  5.10.1.  Boca BEN (PCI, VLB)

  Status -- Supported

  These cards are based on AMD's PCnet chips, used in the AT1500 and the
  like. You can pick up a combo (10BaseT and 10Base2) PCI card for under
  $70 at the moment.

  Perspective buyers should be warned that many users have had endless
  problems with these cards. Owners of fast Pentium systems have been
  especially hit. Note that this is not a driver problem, as it hits
  DOS/Win/NT users as well.  Boca's technical support number is (407)
  241-8088, and you can also reach them at [e-mail].

  Donald did a comparitive test with the above Boca PCI card and a
  similar Allied Telsyn PCnet/PCI implementation, which showed that the
  problem lies in Boca's implementation of the PCnet/PCI chip. These
  test results can be accessed on Don's www server.

  Linux at CESDIS <http://cesdis.gsfc.nasa.gov/linux/>

  Also, Dave Platt has compared the recommended implementation given on
  the AMD data sheet with the Boca implementation, and has determined
  that Boca has left out a substantial number of important filtering
  capacitors. At the risk of being verbose, here is a quote from Dave,
  which will allow you to assess if the problem has been addressed yet,
  given a card for visual inspection.

  ``I just reviewed Appendix B in the 79c970 data sheet.  It recommends
  a _minimum_ of 8 high-frequency bypassing caps (.1 uF multilayer
  ceramic) around the chip, to keep ground and power bounce from causing
  unreliable operation.  Looking at the card I have here, I see a total
  of 5 such caps on the entire card - only a couple of them are close
  enough to the chip to do a decent job of high-frequency bypassing.

  If you hold the card with chips facing up, and the PCI pins pointed
  towards you, the lower-left corner of the '970 has the positioning
  dimple.  The upper-left corner of the chip is the `analog corner',
  where the analog power and ground pins are.  Appendix B calls these
  `the most cricical pins in the layout of a PCnet-PCI card'.  There are
  4 analog power pins, and 2 analog ground pins... all of them are
  supposed to be connected, and properly bypassed.

  On the left side of the chip, the uppermost pin is AVSS1 (analog
  ground 1).  On the top edge, the fourth pin from the left is AVDD3
  (analog power 3).  The Appendix specifically recommends having a .1 uF
  bypass cap tied directly to these two pins (not going through the
  common ground plane).  On the card I have, there is no such cap - the
  nearest bypass cap is about half-an-inch away over by the crystal, and
  is tied to the ground plane.

  The Appendix also specifically recommends `low-frequency bulk
  capacitors' (by which I assume that they mean multi-uF tantalum or
  aluminum electrolytics) as well as high-frequency bypass caps.  I see
  only two bulk capacitors (one 10 uF in the AVSS2/AVDD2 filter circuit,
  and one 4.7 uF up above the chip which also appears to be part of a
  filter circuit).  The Appendix recommends `at least one low-frequency
  bulk (e.g. 22 uF) bypass capactor...  connected directly to the power
  and ground planes.'  There is no capacitor on the board which matches
  this description.

  It appears that Boca ignored _several_ of AMD's recommendations,
  regarding the number, size, placement, and wiring of the power supply
  bypass capacitors.''

  (Thanks Dave.) Boca is offering a `warranty repair' for affected
  owners, which involves adding one of the missing capacitors, but it
  appears that this fix doesn't work 100 percent for most people,
  although it helps some.

  If you are still thinking of buying one of these cards, then at least
  try and get a 7 day unconditional return policy, so that if it doesn't
  work properly in your system, you can return it.

  More general information on the AMD chips can be found in ``AMD
  LANCE''.

  More technical information on AMD LANCE based Ethernet cards can be
  found in ``Notes on AMD...''.

  5.11.  Cabletron

  Donald writes: `Yes, another one of these companies that won't release
  its programming information. They waited for months before actually
  confirming that all their information was proprietary, deliberately
  wasting my time. Avoid their cards like the plague if you can.  Also
  note that some people have phoned Cabletron, and have been told things
  like `a D. Becker is working on a driver for linux' -- making it sound
  like I work for them. This is NOT the case.'

  If you feel like asking them why they don't want to release their low
  level programming info so that people can use their cards, write to
  [e-mail].  Tell them that you are using Linux, and are
  disappointed that they don't support open systems. And no, the usual
  driver development kit they supply is useless. It is just a DOS object
  file that you are supposed to link against. Which you aren't allowed
  to even reverse engineer.

  5.11.1.  E10**, E10**-x, E20**, E20**-x

  Status -- Semi-Supported

  These are NEx000 almost-clones that are reported to work with the
  standard NEx000 drivers, thanks to a ctron-specific check during the
  probe. If there are any problems, they are unlikely to be fixed, as
  the programming information is unavailable.

  5.11.2.  E2100

  Status -- Semi-Supported

  Again, there is not much one can do when the programming information
  is proprietary.  The E2100 is a poor design. Whenever it maps its
  shared memory in during a packet transfer, it maps it into the whole
  128K region! That means you can't safely use another interrupt-driven
  shared memory device in that region, including another E2100.  It will
  work most of the time, but every once in a while it will bite you.
  (Yes, this problem can be avoided by turning off interrupts while
  transferring packets, but that will almost certainly lose clock
  ticks.) Also, if you mis-program the board, or halt the machine at
  just the wrong moment, even the reset button won't bring it back. You
  will have to turn it off and leave it off for about 30 seconds.

  Media selection is automatic, but you can override this with the low
  bits of the dev->mem_end parameter.  See ``PARAM_2''. Module users can
  specify an xcvr=N value on the insmod command line to do the same.

  Also, don't confuse the E2100 for a NE2100 clone.  The E2100 is a
  shared memory NatSemi DP8390 design, roughly similar to a brain-
  damaged WD8013, whereas the NE2100 (and NE1500) use a bus-mastering
  AMD LANCE design.

  There is an E2100 driver included in the standard kernel.  However,
  seeing as programming info isn't available, don't expect bug-fixes.
  Don't use one unless you are already stuck with the card.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.12.  Cogent

  Here is where and how to reach them:

          Cogent Data Technologies, Inc.
          175 West Street, P.O. Box 926
          Friday Harbour, WA 98250, USA.

          Cogent Sales
          15375 S.E. 30th Place, Suite 310
          Bellevue, WA 98007, USA.

          Technical Support:
          Phone [phone] between 8am and 5pm PST
          Fax [phone]
          Compuserve GO COGENT
          Bulletin Board Service [phone]
          Internet: [e-mail]

  5.12.1.  Cogent eMASTER+, EM100, EM400, EM960, EM964

  Status -- Supported

  These are yet another DEC 21040 implementation that should work fine
  with the standard 21040 driver.

  The EM400 and the EM964 are four port cards using a DEC 21050 bridge
  and 4 21040 chips.

  See ``DEC 21040'' for more information on these cards, and the present
  driver situation.

  5.13.  D-Link

  Some people have had difficulty in finding vendors that carry D-link
  stuff. This should help.

                  [phone]  in the US
                  [phone]  in the UK
                  [phone]  in Canada
                  [phone]   in Taiwan

  5.13.1.  DE-100, DE-200, DE-220-T

  Status -- Supported

  The manual says that it is 100 % compatible with the NE2000. This is
  not true. You should call them and tell them you are using their card
  with Linux, and they should correct their documentation. Some
  pre-0.99pl12 driver versions may have trouble recognizing the DE2**
  series as 16 bit cards, and these cards are the most widely reported
  as having the spurious transfer address mismatch errors. Note that
  there are cards from Digital (DEC) that are also named DE100 and
  DE200, but the similarity stops there.

  5.13.2.  DE-520

  Status -- Supported

  This is a PCI card using the PCI version of AMD's LANCE chip.  DMA
  selection and chip numbering information can be found in ``AMD
  LANCE''.

  More technical information on AMD LANCE based Ethernet cards can be
  found in ``Notes on AMD...''.

  5.13.3.  DE-530

  Status -- Supported

  This is a generic DEC 21040 PCI chip implementation, and works with
  the generic 21040 driver.

  See ``DEC 21040'' for more information on these cards, and the present
  driver situation.

  5.13.4.  DE-600

  Status -- Supported

  Laptop users and other folk who might want a quick way to put their
  computer onto the ethernet may want to use this. The driver is
  included with the default kernel source tree.  Bjorn Ekwall
  [e-mail] wrote the driver.  Expect about 180kb/s transfer speed
  from this via the parallel port. You should read the README.DLINK file
  in the kernel source tree.

  Note that the device name that you pass to ifconfig is now eth0 and
  not the previously used dl0.

  If your parallel port is not at the standard 0x378 then you will have
  to recompile. Bjorn writes: ``Since the DE-620 driver tries to sqeeze
  the last microsecond from the loops, I made the irq and port address
  constants instead of variables. This makes for a usable speed, but it
  also means that you can't change these assignements from e.g. lilo;
  you _have_ to recompile...'' Also note that some laptops implement the
  on-board parallel port at 0x3bc which is where the parallel ports on
  monochrome cards were/are.

  5.13.5.  DE-620

  Status -- Supported

  Same as the DE-600, only with two output formats.  Bjorn has written a
  driver for this model, for kernel versions 1.1 and above. See the
  above information on the DE-600.

  5.13.6.  DE-650

  Status -- Semi-Supported

  Some people have been using this PCMCIA card for some time now with
  their notebooks. It is a basic 8390 design, much like a NE2000. The
  LinkSys PCMCIA card and the IC-Card Ethernet (available from Midwest
  Micro) are supposedly DE-650 clones as well.  Note that at present,
  this driver is not part of the standard kernel, and so you will have
  to do some patching.

  See ``PCMCIA Support'' in this document, and if you can, have a look
  at:

  Don's PCMCIA Stuff <http://cesdis.gsfc.nasa.gov/linux/pcmcia.html>

  5.14.  DFI

  5.14.1.  DFINET-300 and DFINET-400

  Status -- Supported

  These cards are now detected (as of 0.99pl15) thanks to Eberhard
  Moenkeberg [e-mail] who noted that they use `DFI' in the first
  3 bytes of the prom, instead of using 0x57 in bytes 14 and 15, which
  is what all the NE1000 and NE2000 cards use. (The 300 is an 8 bit
  pseudo NE1000 clone, and the 400 is a pseudo NE2000 clone.)

  5.15.  Digital / DEC

  5.15.1.  DEPCA, DE100/1, DE200/1/2, DE210, DE422

  Status -- Supported

  As of linux v1.0, there is a driver included as standard for these
  cards. It was written by David C. Davies.  There is documentation
  included in the source file `depca.c', which includes info on how to
  use more than one of these cards in a machine. Note that the DE422 is
  an EISA card. These cards are all based on the AMD LANCE chip.  See
  ``AMD LANCE'' for more info.  A maximum of two of the ISA cards can be
  used, because they can only be set for 0x300 and 0x200 base I/O
  address.  If you are intending to do this, please read the notes in
  the driver source file depca.c in the standard kernel source tree.

  This driver will also work on Alpha CPU based machines, and there are
  various ioctl()s that the user can play with.

  5.15.2.  Digital EtherWorks 3 (DE203, DE204, DE205)

  Status -- Supported

  Included into kernels v1.1.62 and above is this driver, also by David
  C. Davies of DEC. These cards use a proprietary chip from DEC, as
  opposed to the LANCE chip used in the earlier cards like the DE200.
  These cards support both shared memory or programmed I/O, although you
  take about a 50%performance hit if you use PIO mode. The shared memory
  size can be set to 2kB, 32kB or 64kB, but only 2 and 32 have been
  tested with this driver. David says that the performance is virtually
  identical between the 2kB and 32kB mode. There is more information
  (including using the driver as a loadable module) at the top of the
  driver file ewrk3.c and also in README.ewrk3.  Both of these files
  come with the standard kernel distribution.

  The standard driver has a number of interesting ioctl() calls that can
  be used to get or clear packet statistics, read/write the EEPROM,
  change the hardware address, and the like. Hackers can see the source
  code for more info on that one.

  David has also written a configuration utility for this card (along
  the lines of the DOS program NICSETUP.EXE) along with other tools.
  These can be found on sunsite.unc.edu in the directory
  /pub/Linux/system/Network/management -- look for the file ewrk3tools-
  X.XX.tar.gz.

  The next release of this driver (v0.40) will have Alpha CPU support
  like depca.c does and is available from David now if you require it.

  5.15.3.  DE425 (EISA), DE434, DE435, DE500

  Status -- Supported

  These cards are based on the 21040 chip mentioned below.  Included
  into kernels v1.1.86 and above is this driver, also by David C. Davies
  of DEC. It sure is nice to have support from someone on the inside
  ;-) The DE500 uses the newer 21140 chip to provide 10/100Mbs ethernet
  connections.  Have a read of the 21040 section below for extra info.

  Note that as of 1.1.91, David has added a compile time option that
  will allow non-DEC cards to work with this driver. Have a look at
  README.de4x5 for details.

  All the Digital cards will autoprobe for their media (except,
  temporarily, the DE500 due to a patent issue).

  This driver is also ALPHA CPU ready and supports being loaded as a
  module.  Users can access the driver internals through ioctl() calls -
  see the 'ewrk3' tools and the de4x5.c sources for information about
  how to do this.

  5.15.4.  DEC 21040, 21041, 21140, Tulip

  Status -- Supported

  The DEC 21040 is a bus-mastering single chip ethernet solution from
  Digital, similar to AMD's PCnet chip. The 21040 is specifically
  designed for the PCI bus architecture.  SMC's new EtherPower PCI card
  uses this chip.

  You have a choice of two drivers for cards based on this chip. There
  is the DE425 driver discussed above, and the generic 21040 driver that
  Donald has written.

  The updated 21041 chip is also found in place of the 21040 on newly
  produced SMC EtherPower cards.  The 21140 is for supporting 100Base-?
  and works with the Linux drivers for the 21040 chip.  To use David's
  de4x5 driver with non-DEC cards, have a look at README.de4x5 for
  details.

  Donald has used SMC EtherPower-10/100 cards to develop the `tulip'
  driver. Note that the driver that is in the standard kernel tree at
  the moment is not the most up to date version. If you intend on using
  this driver, you should get the newest version from Donald's ftp/WWW
  site.

  Tulip Driver <http://cesdis.gsfc.nasa.gov/linux/drivers/tulip.html>

  The above URL also contains a (non-exhaustive) list of various
  cards/vendors that use the 21040 chip.

  Also note that the tulip driver is still considered an alpha driver
  (see ``Alpha Drivers'') at the moment, and should be treated as such.
  To use it, you will have to edit arch/i386/config.in and uncomment the
  line for CONFIG_DEC_ELCP support.

  5.16.  Farallon

  Farallon sells EtherWave adaptors and transceivers. This device allows
  multiple 10baseT devices to be daisy-chained.

  5.16.1.  Farallon Etherwave

  Status -- Supported

  This is reported to be a 3c509 clone that includes the EtherWave
  transceiver. People have used these successfully with Linux and the
  present 3c509 driver. They are too expensive for general use, but are
  a great option for special cases.  Hublet prices start at $125, and
  Etherwave adds $75-$100 to the price of the board -- worth it if you
  have pulled one wire too few, but not if you are two network drops
  short.

  5.17.  Hewlett Packard

  The 272** cards use programmed I/O, similar to the NE*000 boards, but
  the data transfer port can be `turned off' when you aren't accessing
  it, avoiding problems with autoprobing drivers.

  Thanks to Glenn Talbott for helping clean up the confusion in this
  section regarding the version numbers of the HP hardware.
  5.17.1.  27245A

  Status -- Supported

  8 Bit 8390 based 10BaseT, not recommended for all the 8 bit reasons.
  It was re-designed a couple years ago to be highly integrated which
  caused some changes in initialization timing which only affected
  testing programs, not LAN drivers. (The new card is not `ready' as
  soon after switching into and out of loopback mode.)

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.17.2.  HP PC Lan+ (27247, 27252A)

  Status -- Supported

  The HP PC Lan+ is different to the standard HP PC Lan card. This
  driver was added to the list of drivers in the standard kernel during
  the v1.1.x development cycle. It can be operated in either a PIO mode
  like a ne2000, or a shared memory mode like a wd8013.

  The 47B is a 16 Bit 8390 based 10BaseT w/AUI, and the 52A is a 16 Bit
  8390 based ThinLAN w/AUI.  These cards have 32K onboard RAM for Tx/Rx
  packet buffering instead of the usual 16KB, and they both offer LAN
  connector autosense.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.17.3.  HP-J2405A

  Status -- Supported

  These are lower priced, and slightly faster than the 27247/27252A, but
  are missing some features, such as AUI, ThinLAN connectivity, and boot
  PROM socket.  This is a fairly generic LANCE design, but a minor
  design decision makes it incompatible with a generic `NE2100' driver.
  Special support for it (including reading the DMA channel from the
  board) is included thanks to information provided by HP's Glenn
  Talbott.

  More technical information on LANCE based cards can be found in
  ``Notes on AMD...''

  5.17.4.  HP-Vectra On Board Ethernet

  Status -- Supported

  The HP-Vectra has an AMD PCnet chip on the motherboard.  Earlier
  kernel versions would detect it as the HP-J2405A but that would fail,
  as the Vectra doesn't report the IRQ and DMA channel like the J2405A.
  Get a kernel newer than v1.1.53 to avoid this problem.

  DMA selection and chip numbering information can be found in ``AMD
  LANCE''.

  More technical information on LANCE based cards can be found in
  ``Notes on AMD...''

  5.17.5.  HP 10/100 VG Any Lan Cards (27248B, J2573, J2577, J2585)

  Status -- Supported

  As of early 1.3.x kernels, this driver was made available by Jaroslav
  Kysela, ([e-mail]). Due to the newness of the driver and the
  relatively small number of VG cards in use, feedback on this driver
  has been low.

  Donald has also written a driver for these cards. Unlike the above, it
  is not presently in the standard kernel source tree.  Check out the
  following URL for more information on Donald's 100VG work.

  Donald's 100VG Page
  <http://cesdis.gsfc.nasa.gov/linux/drivers/100vg.html>

  5.18.  IBM / International Business Machines

  5.18.1.  IBM Thinkpad 300

  Status -- Supported

  This is compatible with the Intel based Zenith Z-note.  See ``Z-note''
  for more info.

  Supposedly this site has a comprehensive database of useful stuff for
  newer versions of the Thinkpad. I haven't checked it out myself yet.

  Thinkpad-info <http://peipa.essex.ac.uk/html/linux-thinkpad.html>

  For those without a WWW browser handy, try
  peipa.essex.ac.uk:/pub/tp750/

  5.18.2.  IBM Credit Card Adaptor for Ethernet

  Status -- Semi-Supported

  People have been using this PCMCIA card with Linux as well.  Similar
  points apply, those being that you need a supported PCMCIA chipset on
  your notebook, and that you will have to patch the PCMCIA support into
  the standard kernel.

  See ``PCMCIA Support'' in this document, and if you can, have a look
  at:

  Don's PCMCIA Stuff <http://cesdis.gsfc.nasa.gov/linux/pcmcia.html>

  5.18.3.  IBM Token Ring

  Status -- Semi-Supported

  To support token ring requires more than only writing a device driver,
  it also requires writing the source routing routines for token ring.
  It is the source routing that would be the most time comsuming to
  write.

  Peter De Schrijver has been spending some time on Token Ring lately.
  and has worked with IBM ISA and MCA token ring cards.

  The present token ring code has been included into the first of the
  1.3.x series kernels.

  Peter says that it was originally tested on an MCA 16/4 Megabit Token
  Ring board, but it should work with other Tropic based boards.

  5.19.  ICL Ethernet Cards

  5.19.1.  ICL EtherTeam 16i/32

  Status -- Supported

  Mika Kuoppala ([e-mail]) wrote this driver, and it was
  included into early 1.3.4x kernels. It uses the Fujitsu MB86965 chip
  that is also used on the at1700 cards.

  5.20.  Intel Ethernet Cards

  5.20.1.  Ether Express

  Status -- Semi-Supported

  This card uses the intel i82586. (Surprise, huh?)  The driver is in
  the standard release of the kernel, as an alpha driver. See ``Alpha
  Drivers'' for important information on using alpha-test ethernet
  drivers with Linux.

  The reason is that the driver works well with slow machines, but the
  i82586 occasionally hangs from the packet buffer contention that a
  fast machine can cause.  One reported hack/fix is to change all of the
  outw() calls to outw_p(). Also, the driver is missing promiscuous and
  multicast modes. (See ``Multicast and...'')

  There is also the standard way of using the chip (read slower) that is
  described in the chip manual, and used in other i82586 drivers, but
  this would require a re-write of the entire driver.

  There is some technical information available on the i82586 in
  ``Programming the Intel Chips'' and also in the source code for the
  driver `eexpress.c'. Don't be afraid to read it. ;-)

  5.20.2.  Ether Express PRO/10

  Status -- Supported

  Bao Chau Ha has written a driver for these cards that has been
  included into early 1.3.x kernels. It may also work with some of the
  Compaq built-in ethernet systems that are based on the i82595 chip.

  5.20.3.  Ether Express PRO/100

  Status -- Not Supported

  These PCI and EISA cards use a different chip that the PRO/10 cards
  do. Bao is currently trying to get a datasheet out of Intel without
  having to sign a NDA. Good Luck!

  5.21.  LinkSys

  5.21.1.  LinkSys Pocket Ethernet Adapter Plus (PEAEPP)

  Status -- Supported

  This is supposedly a DE-620 clone, and is reported to work well with
  that driver. See ``DE-620'' for more information.

  5.21.2.  LinkSys PCMCIA Adaptor

  Status -- Supported

  This is supposed to be a re-badged DE-650. See ``DE-650'' for more
  information.

  5.22.  Microdyne

  5.22.1.  Microdyne Exos 205T

  Status -- Semi-Supported

  Another i82586 based card. Dirk Niggemann [e-mail] has
  written a driver that he classes as ``pre-alpha'' that he would like
  people to test. Mail him for more details.

  5.23.  Mylex

  Mylex can be reached at the following numbers, in case anyone wants to
  ask them anything.

          MYLEX CORPORATION, Fremont
          Sales:  800-77-MYLEX, [phone]
          FAX:    [phone].

  5.23.1.  Mylex LNP101

  Status -- Supported

  This is a PCI card that is based on DEC's 21040 chip.  It is
  selectable between 10BaseT, 10Base2 and 10Base5 output.  The LNP101
  card has been verified to work with the generic 21040 driver.

  See the section on the 21040 chip (``DEC 21040'') for more
  information.

  5.23.2.  Mylex LNP104

  Status -- Not Supported

  The LNP104 uses the DEC 21050 chip to deliver four independent 10BaseT
  ports. It may work with 21040 drivers, but nobody has tried yet.

  5.23.3.  Mylex M390B EISA

  Status -- Not Supported

  Russ writes that "...it's a fairly vanilla 8390-based adapter.  Only
  really tricky thing is that, like the Interlan es3210, you MUST do
  only 32-bit transfers to/from the board.  Look at the Crynwr packet
  driver and try making the changes yourself...''

  5.24.  Novell Ethernet, NExxxx and associated clones.

  The prefix `NE' came from Novell Ethernet. Novell followed the
  cheapest NatSemi databook design and sold the manufacturing rights
  (spun off?) Eagle, just to get reasonably-priced ethercards into the
  market. (The now ubiquitous NE2000 card.)

  5.24.1.  NE1000, NE2000

  Status -- Supported

  NOTE: If you are using a kernel that is older than v1.2.9, it is
  strongly recommended that you upgrade to a newer version. There was an
  important bugfix made to the ne driver in 1.2.7, and another important
  bugfix made to the upper layers (dev.c) in 1.2.9. Both of these bugs
  can cause a ne2000 card to hang your computer.

  The ne2000 is now a generic name for a bare-bones design around the
  NatSemi 8390 chip. They use programmed I/O rather than shared memory,
  leading to easier installation but slightly lower performance and a
  few problems. Again, the savings of using an 8 bit NE1000 over the
  NE2000 are only warranted if you expect light use. Some recently
  introduced NE2000 clones use the National Semiconductor `AT/LANTic'
  83905 chip, which offers a shared memory mode similar to the 8013 and
  EEPROM or software configuration. Some problems can arise with poor
  NE2000 clones. See ``Problems with...'', and ``Poor NE2000 Clones'' In
  general it is not a good idea to put a NE2000 clone at I/O address
  0x300 because nearly every device driver probes there at boot. Some
  poor NE2000 clones don't take kindy to being prodded in the wrong
  areas, and will respond by locking your machine.

  Donald has written a NE2000 diagnostic program, but it is still
  presently in alpha test. (ne2k) See ``Diagnostic Programs'' for more
  information.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.24.2.  NE1500, NE2100

  Status -- Supported

  These cards use the original 7990 LANCE chip from AMD and are
  supported using the Linux lance driver. Newer NE2100 clones use the
  updated PCnet/ISA chip from AMD.

  Some earlier versions of the lance driver had problems with getting
  the IRQ line via autoIRQ from the original Novell/Eagle 7990 cards.
  Hopefully this is now fixed.  If not, then specify the IRQ via LILO,
  and let us know that it still has problems.

  DMA selection and chip numbering information can be found in ``AMD
  LANCE''.

  More technical information on LANCE based cards can be found in
  ``Notes on AMD...''

  5.24.3.  NE3200

  Status -- Not Supported

  This card uses a lowly 8MHz 80186, and hence you are better off using
  a cheap NE2000 clone. Even if a driver was available, the NE2000 card
  would most likely be faster.

  5.25.  Pure Data

  5.25.1.  PDUC8028, PDI8023

  Status -- Supported

  The PureData PDUC8028 and PDI8023 series of cards are reported to
  work, thanks to special probe code contributed by Mike Jagdis
  [e-mail]. The support is integrated with the WD
  driver.

  5.26.  Racal-Interlan

  5.26.1.  NI5210

  Status -- Semi-Supported

  Michael Hipp has written a driver for this card. It is included in the
  standard kernel as an `alpha' driver. Michael would like to hear
  feedback from users that have this card. See ``Alpha Drivers'' for
  important information on using alpha-test ethernet drivers with Linux.

  Michael says that ``the internal sysbus seems to be slow.  So we often
  lose packets because of overruns while receiving from a fast remote
  host.''

  This card also uses one of the Intel chips. See ``Programming the
  Intel Chips'' for more technical information.

  5.26.2.  NI6510 (not EB)

  Status -- Semi-Supported

  There is also a driver for the LANCE based NI6510, and it is also
  written by Michael Hipp. Again, it is also an `alpha' driver. For some
  reason, this card is not compatible with the generic LANCE driver. See
  ``Alpha Drivers'' for important information on using alpha-test
  ethernet drivers with Linux.

  5.26.3.  EtherBlaster (aka NI6510EB)

  Status -- Supported

  As of kernel 1.3.23, the generic LANCE driver had a check added to it
  for the 0x52, 0x44 NI6510EB specific signature.  Others have reported
  that this signature is not the same for all NI6510EB cards however,
  which will cause the lance driver to not detect your card. If this
  happens to you, you can change the probe (at about line 322 in
  lance.c) to printk() out what the values are for your card and then
  use them instead of the 0x52, 0x44 defaults.

  The cards should probably be run in `high-performance' mode and not in
  the NI6510 compatible mode when using the lance driver.

  5.27.  Sager

  5.27.1.  Sager NP943

  Status -- Semi-Supported

  This is just a 3c501 clone, with a different S.A. PROM prefix. I
  assume it is equally as brain dead as the original 3c501 as well.
  Kernels 1.1.53 and up check for the NP943 i.d. and then just treat it
  as a 3c501 after that. See ``3Com 3c501'' for all the reasons as to
  why you really don't want to use one of these cards.

  5.28.  Schneider & Koch

  5.28.1.  SK G16

  Status -- Supported

  This driver was included into the v1.1 kernels, and it was written by
  PJD Weichmann and SWS Bern. It appears that the SK G16 is similar to
  the NI6510, in that it is based on the first edition LANCE chip (the
  7990). Once again, it appears as though this card won't work with the
  generic LANCE driver.

  5.29.  SEEQ

  5.29.1.  SEEQ 8005

  Status -- Supported

  This driver was included into early 1.3.x kernels, and was written by
  Hamish Coleman.  There is little information about the card included
  in the driver, and hence little information to be put here. If you
  have a question, you are probably best off e-mailing
  [e-mail]

  5.30.  SMC (Standard Microsystems Corp.)

  Please see ``Western Digital'' for information on SMC cards.

  5.31.  Thomas Conrad

  5.31.1.  Thomas Conrad TC-5048

  This is yet another PCI card that is based on DEC's 21040 chip.

  See the section on the 21040 chip (``DEC 21040'') for more
  information.

  5.32.  Western Digital / SMC

  The ethernet part of Western Digital has been bought out by SMC.  One
  common mistake people make is that the relatively new SMC Elite Ultra
  is the same as the older SMC Elite16 models -- this is not the case.

  Here is how to contact SMC (not that you should need to.)

       SMC / Standard Microsystems Corp., 80 Arkay Drive, Hauppage,
       New York, 11788, USA.

  Technical Support via phone:

          800-992-4762 (USA)
          800-433-5345 (Canada)
          516-435-6250 (Other Countries)

  Literature requests:

          800-SMC-4-YOU (USA)
          800-833-4-SMC (Canada)
          516-435-6255  (Other Countries)

  Technical Support via E-mail:

          [e-mail]

  FTP Site:

          ftp.smc.com

  5.32.1.  WD8003, SMC Elite

  Status -- Supported

  These are the 8-bit versions of the card. The 8 bit 8003 is slightly
  less expensive, but only worth the savings for light use. Note that
  some of the non-EEPROM cards (clones with jumpers, or old old old
  wd8003 cards) have no way of reporting the IRQ line used. In this
  case, auto-irq is used, and if that fails, the driver silently assings
  IRQ 5.  Information regarding what the jumpers on old non-EEPROM
  wd8003 cards do can be found in conjunction with the SMC setup/driver
  disks stored on dorm.rutgers.edu in the directory
  /pub/novell/nic_drvs/. Note that some of the newer SMC `SuperDisk'
  programs will fail to detect the old EEPROM-less cards. The file
  SMCDSK46.EXE seems to be a good all-round choice. Also the jumper
  settings for old cards are in an ascii text file in the aforementioned
  archive. The latest (greatest?) version can be obtained from
  ftp.smc.com.

  As these are basically the same as their 16 bit counterparts (WD8013 /
  SMC Elite16), you should see the next section for more information.

  5.32.2.  WD8013, SMC Elite16

  Status -- Supported

  Over the years the design has added more registers and an EEPROM.
  Clones usually go by the `8013' name, and usually use a non-EEPROM
  (jumpered) design.  Late model SMC cards will have two main PLCC chips
  on board; the SMC 83c690 and the SMC 83c694.  The shared memory design
  makes the cards 10-20 % faster, than PIO cards, especially with larger
  packets.  More importantly, from the driver's point of view, it avoids
  a few bugs in the programmed-I/O mode of the 8390, allows safe multi-
  threaded access to the packet buffer, and it doesn't have a
  programmed-I/O data register that hangs your machine during warm-boot
  probes.

  Non-EEPROM cards that can't just read the selected IRQ will attempt
  auto-irq, and if that fails, they will silently assign IRQ 10. (8 bit
  versions will assign IRQ 5)

  Cards with a non standard amount of memory on board can have the
  memory size specified at boot (or at `insmod' time if using modules).
  The standard memory size is 8kB for an 8bit card and 16kB for a 16bit
  card.  For example, the older WD8003EBT cards could be jumpered for
  32kB memory. To make full use of that RAM, you would use something
  like (for i/o=0x280 and IRQ 9):

  ______________________________________________________________________
          LILO: linux ether=9,0x280,0xd0000,0xd8000,eth0
  ______________________________________________________________________

  Also see ``8013 problems'' for some of the more common problems that
  people have.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.32.3.  SMC Elite Ultra

  Status -- Supported

  This ethercard is based on a new chip from SMC, with a few new
  features. While it has a mode that is similar to the older SMC
  ethercards, it's not entirely compatible with the old WD80*3 drivers.
  However, in this mode it shares most of its code with the other 8390
  drivers, while operating slightly faster than a WD8013 clone.

  Since part of the Ultra looks like an 8013, the Ultra probe is
  supposed to find an Ultra before the wd8013 probe has a chance to
  mistakenly identify it.

  Donald mentioned that it is possible to write a separate driver for
  the Ultra's `Altego' mode which allows chaining transmits at the cost
  of inefficient use of receive buffers, but that will probably not
  happen.

  Bus-Master SCSI host adaptor users take note: In the manual that ships
  with Interactive UNIX, it mentions that a bug in the SMC Ultra will
  cause data corruption with SCSI disks being run from an aha-154X host
  adaptor.  This will probably bite aha-154X compatible cards, such as
  the BusLogic boards, and the AMI-FastDisk SCSI host adaptors as well.

  SMC has acknowledged the problem occurs with Interactive, and older
  Windows NT drivers. It is a hardware conflict with early revisions of
  the card that can be worked around in the driver design. The current
  Ultra driver protects against this by only enabling the shared memory
  during data transfers with the card. Make sure your kernel version is
  at least 1.1.84, or that the driver version reported at boot is at
  least smc-ultra.c:v1.12 otherwise you are vulnerable.

  If you intend on using this driver as a loadable module you should
  probably see ``Using the Ethernet Drivers as Modules'' and also ``8390
  Based Cards as Modules'' for module specific information.

  5.32.4.  SMC 8416 (EtherEZ)

  Status -- Supported

  This card uses SMC's 83c795 chip and supports the Plug 'n Play
  specification. It also has an SMC Ultra compatible mode, which allows
  it to be used with the Linux Ultra driver.  In this compatibility
  mode, it uses shared memory instead of programmed i/o. Be sure to set
  your card for this compatibility mode. See the above information for
  notes on the Ultra driver.

  Note that the EtherEZ specific checks were added to the SMC Ultra
  driver in 1.1.84, and hence earlier kernel versions will not detect or
  handle these cards correctly.

  5.32.5.  SMC 8432 PCI (EtherPower)

  Status -- Supported

  These cards are a basic DEC 21040 implementation, i.e. one big chip
  and a couple of transceivers. Donald has used one of these cards for
  his development of the generic 21040 driver (aka tulip.c). Thanks to
  Duke Kamstra, once again, for supplying a card to do development on.

  Some of the newer revisons of this card use the newer DEC 21041 chip,
  which may cause problems with older versions of the tulip driver. Make
  sure you are using the latest driver release.

  See ``DEC 21040'' for more details on using one of these cards, and
  the current status of the driver.

  5.32.6.  SMC 3008

  Status -- Not Supported

  These 8 bit cards are based on the Fujitsu MB86950, which is an
  ancient version of the MB86965 used in the Linux at1700 driver. Russ
  says that you could probably hack up a driver by looking at the
  at1700.c code and his DOS packet driver for the Tiara card (tiara.asm)

  5.32.7.  SMC 3016

  Status -- Not Supported

  These are 16bit i/o mapped 8390 cards, much similar to a generic
  NE2000 card. If you can get the specifications from SMC, then porting
  the NE2000 driver would probably be quite easy.

  5.32.8.  SMC 9000

  Status -- Not Supported

  These cards are VLB cards based on the 91c92 chip. They are fairly
  expensive, and hence the demand for a driver is pretty low at the
  moment.

  5.33.  Xircom

  Another group that won't release documentation. No cards supported.
  Don't look for any support in the future unless they release their
  programming information. And this is highly unlikely, as they forbid
  you from even reverse- engineering their drivers. If you are already
  stuck with one, see if you can trade it off on some DOS (l)user.

  And if you just want to verify that this is the case, you can reach
  Xircom at 1-800-874-7875, 1-800-438-4526 or [phone].  They
  used to advertise that their products "work with all network operating
  systems", but have since stopped. Wonder why...

  5.33.1.  PE1, PE2, PE3-10B*

  Status -- Not Supported

  Not to get your hopes up, but if you have one of these parallel port
  adaptors, you may be able to use it in the DOS emulator with the
  Xircom-supplied DOS drivers. You will have to allow DOSEMU access to
  your parallel port, and will probably have to play with SIG (DOSEMU's
  Silly Interrupt Generator).

  5.34.  Zenith

  5.34.1.  Z-Note

  Status -- Supported

  The built-in Z-Note network adaptor is based on the Intel i82593 using
  two DMA channels. There is an (alpha?) driver available in the present
  kernel version. As with all notebook and pocket adaptors, it is under
  the `Pocket and portable adaptors' section when running make config.
  See ``Programming the Intel chips'' for more technical information.
  Also note that the IBM ThinkPad 300 is compatible with the Z-Note.

  5.35.  Znyx

  5.35.1.  Znyx ZX342 (DEC 21040 based)

  Status -- Supported

  You have a choice of two drivers for cards based on this chip. There
  is the DE425 driver written by David, and the generic 21040 driver
  that Donald has written.

  Note that as of 1.1.91, David has added a compile time option that may
  allow non-DEC cards (such as the Znyx cards) to work with this driver.
  Have a look at README.de4x5 for details.

  See ``DEC 21040'' for more information on these cards, and the present
  driver situation.

  5.36.  Drivers for Non-Ethernet Devices

  There are a few other drivers that are in the linux source, that
  present an ethernet-like device to network programs, while not really
  being ethernet. These are briefly listed here for completeness.

  dummy.c - The purpose of this driver is to provide a device to point a
  route through, but not to actually transmit packets.

  eql.c - Load Equalizer, enslaves multiple devices (usually modems) and
  balances the Tx load across them while presenting a single device to
  the network programs.

  ibmtr.c - IBM Token Ring, which is not really ethernet.  Broken-Ring
  requires source routing and other uglies.

  loopback.c - Loopback device, for which all packets from you machine
  and destined for your own machine go.  It essentially just moves the
  packet off the Tx queue and onto the Rx queue.

  pi2.c - Ottawa Amateur Radio Club PI and PI2 interface.

  plip.c - Parallel Line Internet Protocol, allows two computers to send
  packets to each other over two joined parallel ports in a point-to-
  point fashion.

  ppp.c - Point-to-Point Protocol (RFC1331), for the Transmission of
  Multi-protocol Datagrams over a Point-to-Point Link (again usually
  modems).

  slip.c - Serial Line Internet Protocol, allows two computers to send
  packets to each other over two joined serial ports (usually via
  modems) in a point-to-point fashion.

  tunnel.c - Provides an IP tunnel through which you can tunnel network
  traffic transparently across subnets

  wavelan.c - An Ethernet-like radio transceiver controlled by the Intel
  82586 coprocessor which is used on other ethercards such as the Intel
  EtherExpress.

  6.  Cables, Coax, Twisted Pair

  If you are starting a network from scratch, it's considerably less
  expensive to use thin ethernet, RG58 co-ax cable with BNC connectors,
  than old-fashioned thick ethernet, RG-5 cable with N connectors, or
  10baseT, twisted pair telco-style cables with RJ-45 eight wire `phone'
  connectors. See ``Type of cable...'' for an introductory look at
  cables.

  Also note that the FAQ from comp.dcom.lans.ethernet has a lot of
  useful information on cables and such. Look in dorm.rutgers.edu for
  the file /pub/novell/info_and_docs/Ethernet.FAQ

  6.1.  Thin Ethernet (thinnet)

  Thin ethernet is the `ether of choice'. The cable is inexpensive. If
  you are making your own cables solid-core RG58A is $0.27/m. and
  stranded RG58AU is $0.45/m. Twist-on BNC connectors are < $2 ea., and
  other misc. pieces are similarly inexpensive. It is essential that you
  properly terminate each end of the cable with 50 ohm terminators, so
  budget $2 ea. for a pair. It's also vital that your cable have no
  `stubs' -- the `T' connectors must be attached directly to the
  ethercards. The only drawback is that if you have a big loop of
  machines connected together, and some bonehead breaks the loop by
  taking one cable off the side of his tee, the whole network goes down
  because it sees an infinite impedance (open circuit) instead of the
  required 50 ohm termination. Note that you can remove the tee piece
  from the card itself without killing the whole subnet, as long as you
  don't remove the cables from the tee itself. Of course this will
  disturb the machine that you pull the actual tee off of. 8-) And if
  you are doing a small network of two machines, you still need the tees
  and the 50 ohm terminators -- you can't just cable them together!

  6.2.  Twisted Pair

  Twisted pair networks require active hubs, which start around $200,
  and the raw cable cost can actually be higher than thinnet. They are
  usually sold using the claim that you can use your existing telephone
  wiring, but it's a rare installation where that turns out to be the
  case. The claim that you can upgrade to higher speeds is also suspect,
  as most proposed schemes use higher-grade (read $$) cable and more
  sophisticated termination ($$$) than you would likely install on
  speculation. New gizmos are floating around which allow you to daisy-
  chain machines together, and the like. For example, Farallon sells
  EtherWave adaptors and transceivers. This device allows multiple
  10baseT devices to be daisy-chained. They also sell a 3c509 clone that
  includes the EtherWave transceiver.  The drawback is that it's more
  expensive and less reliable than a cheap ($100-$150) mini-hub and
  another ethercard.  You probably should either go for the hub approach
  or switch over to 10base2 thinnet.

  On the other hand, hubs are rapidly dropping in price, all 100Mb/sec
  ethernet proposals use twisted pair, and most new business
  installations use twisted pair. (This is probably to avoid the problem
  with idiots messing with the BNC's as described above.)

  Also, Russ Nelson adds that `New installations should use Category 5
  wiring. Anything else is a waste of your installer's time, as 100Base-
  whatever is going to require Cat 5.'

  If you are only connecting two machines, it is possible to avoid using
  a hub, by swapping the Rx and Tx pairs (1-2 and 3-6).

  If you hold the RJ-45 connector facing you (as if you were going to
  plug it into your mouth) with the lock tab on the top, then the pins
  are numbered 1 to 8 from left to right. The pin usage is as follows:

          Pin Number              Assignment
          ----------              ----------
          1                       Output Data (+)
          2                       Output Data (-)
          3                       Input Data (+)
          4                       Reserved for Telephone use
          5                       Reserved for Telephone use
          6                       Input Data (-)
          7                       Reserved for Telephone use
          8                       Reserved for Telephone use

  Some cards, like the wd8013 can sense reversed polarity, and will
  adjust accordingly. Also note that 3 and 6 must be a twisted pair. If
  you make 3-4 a twisted pair, and 5-6 the other twisted pair, your
  cable may work for lengths less than a metre, but will fail miserably
  for longer lengths.

  Note that before 10BaseT was ratified as a standard, there existed
  other network formats using RJ-45 connectors, and the same wiring
  scheme as above. Examples are SynOptics's LattisNet, and AT&T's
  StarLAN.  In some cases, (as with early 3C503 cards) you could set
  jumpers to get the card to talk to hubs of different types, but in
  most cases cards designed for these older types of networks will not
  work with standard 10BaseT networks/hubs. (Note that if the cards also
  have an AUI port, then there is no reason as to why you can't use
  that, combined with an AUI to 10BaseT transceiver.)

  6.3.  Thick Ethernet

  Thick ethernet is mostly obsolete, and is usually used only to remain
  compatible with an existing implementation. You can stretch the rules
  and connect short spans of thick and thin ethernet together with a
  passive $3 N-to-BNC connector, and that's often the best solution to
  expanding an existing thicknet. A correct (but expensive) solution is
  to use a repeater in this case.

  7.  Software Configuration and Card Diagnostics

  In most cases, if the configuration is done by software, and stored in
  an EEPROM, you will usually have to boot DOS, and use the supplied DOS
  program to set the cards IRQ, I/O, mem_addr and whatnot. Besides,
  hopefully it is something you will only be setting once. For those
  that don't have the DOS utility available, note that a fair number of
  NIC setup/driver disks (e.g. 3Com, SMC/WD and Allied Telesis NIC's)
  are available from dorm.rutgers.edu in the directory
  /pub/novell/nic_drvs/ However, there are some cards for which Linux
  versions of the config utils exist, and they are listed here.

  Also, Donald has written a few small card diagnostic programs that run
  under Linux. Most of these are a result of debugging tools that he has
  created while writing the various drivers. Don't expect fancy menu-
  driven interfaces. You will have to read the source code to use most
  of these. Even if your particular card doesn't have a corresponding
  diagnostic, you can still get lots of information just by typing cat
  /proc/net/dev -- assuming that your card was at least detected at
  boot.

  In either case, you will have to run most of these programs as root
  (to allow I/O to the ports) and you probably want to shut down the
  ethercard before doing so by typing ifconfig eth0 down (Note: replace
  eth0 with atp0 or whatever when appropriate.)

  7.1.  Configuration Programs for Ethernet Cards

  For people with wd80x3 cards, there is the program wdsetup which can
  be found in wdsetup-0.6a.tar.gz on Linux ftp sites.  I am not sure if
  it is being actively maintained or not, as it has not been updated for
  quite a while. If it works fine for you then great, if not, use the
  DOS version that you should have got with your card. If you don't have
  the DOS version, you will be glad to know that the SMC setup/driver
  disks are available at the dorm.rutgers.edu site mentioned above.  Of
  course, you have to have an EEPROM card to use this utility.  Old, old
  wd8003 cards, and some wd8013 clones use jumpers to set up the card
  instead.

  The Digital EtherWorks 3 card can be configured in a similar fashion
  to the DOS program NICSETUP.EXE. David C. Davies wrote this and other
  tools for the EtherWorks 3 in conjunction with the driver. Look on
  sunsite.unc.edu in the directory /pub/linux/system/Network/management
  for the file that is named ewrk3tools-X.XX.tar.gz.

  Some Nat Semi DP83905 implementations (such as the AT/LANTIC and the
  NE2000+) are software configurable. (Note that this card can also
  emulate a wd8013!) You can get the file /pub/linux/setup/atlantic.c
  from Donald's ftp server, cesdis.gsfc.nasa.gov to configure this card.
  Be careful when configuring NE2000+ cards, as you can give them bad
  setting values which will require you to open the case and switch a
  jumper to force it back to sane settings.

  The 3Com Etherlink III family of cards (i.e. 3c5x9) can be configured
  by using another config utility from Donald.  You can get the file
  /pub/linux/setup/3c5x9setup.c from Donald's ftp server,
  cesdis.gsfc.nasa.gov to configure these cards. (Note that the DOS
  3c5x9B config utility may have more options pertaining to the new
  ``B'' series of the Etherlink III family.)

  7.2.  Diagnostic Programs for Ethernet Cards

  Any of the diagnostic programs that Donald has written can be obtained
  from this URL.

  Ethercard Diagnostics
  <http://cesdis.gsfc.nasa.gov/pub/linux/diag/diagnostic.html>

  Allied Telesis AT1700 -- look for the file /pub/linux/diag/at1700.c on
  cesdis.gsfc.nasa.gov.

  Cabletron E21XX -- look for the file /pub/linux/diag/e21.c on
  cesdis.gsfc.nasa.gov.

  HP PCLAN+ -- look for the file /pub/linux/diag/hp+.c on
  cesdis.gsfc.nasa.gov.

  Intel EtherExpress -- look for the file /pub/linux/diag/eexpress.c on
  cesdis.gsfc.nasa.gov.

  NE2000 cards -- look for the file /pub/linux/diag/ne2k.c on
  cesdis.gsfc.nasa.gov.

  RealTek (ATP) Pocket adaptor -- look for the file /pub/linux/diag/atp-
  diag.c on cesdis.gsfc.nasa.gov.

  All Other Cards -- try typing cat /proc/net/dev and see what useful
  info the kernel has on the card in question.

  8.  Technical Information

  For those who want to play with the present drivers, or try to make up
  their own driver for a card that is presently unsupported, this
  information should be useful. If you do not fall into this category,
  then perhaps you will want to skip this section.

  8.1.  Probed Addresses

  While trying to determine what ethernet card is there, the following
  addresses are autoprobed, assuming the type and specs of the card have
  not been set in the kernel. The file names below are in
  /usr/src/linux/drivers/net/

  ______________________________________________________________________
          3c501.c         0x280, 0x300
          3c503.c:        0x300, 0x310, 0x330, 0x350, 0x250, 0x280, 0x2a0, 0x2e0
          3c505.c:        0x300, 0x280, 0x310
          3c507.c:        0x300, 0x320, 0x340, 0x280
          3c509.c:        Special ID Port probe
          apricot.c       0x300
          at1700.c:       0x300, 0x280, 0x380, 0x320, 0x340, 0x260, 0x2a0, 0x240
          atp.c:          0x378, 0x278, 0x3bc
          depca.c         0x300, 0x200
          de600.c:        0x378
          de620.c:        0x378
          eexpress.c:     0x300, 0x270, 0x320, 0x340
          hp.c:           0x300, 0x320, 0x340, 0x280, 0x2C0, 0x200, 0x240
          hp-plus.c       0x200, 0x240, 0x280, 0x2C0, 0x300, 0x320, 0x340
          lance.c:        0x300, 0x320, 0x340, 0x360
          ne.c:           0x300, 0x280, 0x320, 0x340, 0x360
          ni52.c          0x300, 0x280, 0x360, 0x320, 0x340
          ni65.c          0x300, 0x320, 0x340, 0x360
          smc-ultra.c:    0x200, 0x220, 0x240, 0x280, 0x300, 0x340, 0x380
          wd.c:           0x300, 0x280, 0x380, 0x240
  ______________________________________________________________________

  There are some NE2000 clone ethercards out there that are waiting
  black holes for autoprobe drivers. While many NE2000 clones are safe
  until they are enabled, some can't be reset to a safe mode.  These
  dangerous ethercards will hang any I/O access to their `dataports'.
  The typical dangerous locations are:

  ______________________________________________________________________
          Ethercard jumpered base     Dangerous locations (base + 0x10 - 0x1f)
                  0x300 *                         0x310-0x317
                  0x320                           0x330-0x337
                  0x340                           0x350-0x357
                  0x360                           0x370-0x377
  ______________________________________________________________________

  * The 0x300 location is the traditional place to put an ethercard, but
  it's also a popular place to put other devices (often SCSI
  controllers). The 0x320 location is often the next one chosen, but
  that's bad for for the AHA1542 driver probe. The 0x360 location is
  bad, because it conflicts with the parallel port at 0x378.  If you
  have two IDE controllers, or two floppy controlers, then 0x360 is also
  a bad choice, as a NE2000 card will clobber them as well.

  Note that kernels > 1.1.7X keep a log of who uses which i/o ports, and
  will not let a driver use i/o ports registered by an earlier driver.
  This may result in probes silently failing.  You can view who is using
  what i/o ports by typing cat /proc/ioports if you have the proc
  filesystem enabled.

  To avoid these lurking ethercards, here are the things you can do:

  ╖  Probe for the device's BIOS in memory space. This is easy and
     always safe, but it only works for cards that always have BIOSes,
     like primary SCSI controllers.

  ╖  Avoid probing any of the above locations until you think you've
     located your device. The NE2000 clones have a reset range from
     <base>+0x18 to <base>+0x1f that will read as 0xff, so probe there
     first if possible. It's also safe to probe in the 8390 space at
     <base>+0x00 - <base>+0x0f, but that area will return quasi-random
     values

  ╖  If you must probe in the dangerous range, for instance if your
     target device has only a few port locations, first check that there
     isn't an NE2000 there. You can see how to do this by looking at the
     probe code in /usr/src/linux/net/inet/ne.c

  ╖  Use the `reserve' boot time argument to protect volatile areas from
     being probed. See the information on using boot time arguments with
     LILO in ``The reserve command''

  8.2.  Writing a Driver

  The only thing that one needs to use an ethernet card with Linux is
  the appropriate driver. For this, it is essential that the
  manufacturer will release the technical programming information to the
  general public without you (or anyone) having to sign your life away.
  A good guide for the likelihood of getting documentation (or, if you
  aren't writing code, the likelihood that someone else will write that
  driver you really, really need) is the availability of the Crynwr (nee
  Clarkson) packet driver. Russ Nelson runs this operation, and has been
  very helpful in supporting the development of drivers for Linux. Net-
  surfers can try this URL to look up Russ' software.

  Russ Nelson's Packet Drivers <http://www.crynwr.com/crynwr/home.html>

  Given the documentation, you can write a driver for your card and use
  it for Linux (at least in theory).  Keep in mind that some old
  hardware that was designed for XT type machines will not function very
  well in a multitasking environment such as Linux. Use of these will
  lead to major problems if your network sees a reasonable amount of
  traffic.

  Most cards come with drivers for MS-DOS interfaces such as NDIS and
  ODI, but these are useless for Linux. Many people have suggested
  directly linking them in or automatic translation, but this is nearly
  impossible. The MS-DOS drivers expect to be in 16 bit mode and hook
  into `software interrupts', both incompatible with the Linux kernel.
  This incompatibility is actually a feature, as some Linux drivers are
  considerably better than their MS-DOS counterparts. The `8390' series
  drivers, for instance, use ping-pong transmit buffers, which are only
  now being introduced in the MS-DOS world.

  (Ping-pong Tx buffers means using at least 2 max-size packet buffers
  for Tx packets. One is loaded while the card is transmitting the
  other. The second is then sent as soon as the first finished, and so
  on. In this way, most cards are able to continuously send back-to-back
  packets onto the wire.)

  OK. So you have decided that you want to write a driver for the Foobar
  Ethernet card, as you have the programming information, and it hasn't
  been done yet. (...these are the two main requirements ;-) You should
  start with the skeleton network driver that is provided with the Linux
  kernel source tree. It can be found in the file
  /usr/src/linux/drivers/net/skeleton.c in all recent kernels.

  8.3.  Driver interface to the kernel

  Here are some notes on the functions that you would have to write if
  creating a new driver. Reading this in conjunction with the above
  skeleton driver may help clear things up.

  8.3.1.  Probe

  Called at boot to check for existence of card. Best if it can check
  un-obtrsively by reading from memory, etc. Can also read from i/o
  ports. Initial writing to i/o ports in a probe is not good as it may
  kill another device.  Some device initialization is usually done here
  (allocating i/o space, IRQs,filling in the dev->??? fields etc.)  You
  need to know what io ports/mem the card can be configured to, how to
  enable shared memory (if used) and how to select/enable interrupt
  generation, etc.

  8.3.2.  Interrupt handler

  Called by the kernel when the card posts an interrupt.  This has the
  job of determining why the card posted an interrupt, and acting
  accordingly. Usual interrupt conditions are data to be rec'd, transmit
  completed, error conditions being reported. You need to know any
  relevant interrupt status bits so that you can act accordingly.

  8.3.3.  Transmit function

  Linked to dev->hard_start_xmit() and is called by the kernel when
  there is some data that the kernel wants to put out over the device.
  This puts the data onto the card and triggers the transmit. You need
  to know how to bundle the data and how to get it onto the card (shared
  memory copy, PIO transfer, DMA?) and in the right place on the card.
  Then you need to know how to tell the card to send the data down the
  wire, and (possibly) post an interrupt when done.  When the hardware
  can't accept additional packets it should set the dev->tbusy flag.
  When additional room is available, usually during a transmit-complete
  interrupt, dev->tbusy should be cleared and the higher levels informed
  with mark_bh(INET_BH).

  8.3.4.  Receive function

  Called by the kernel interrupt handler when the card reports that
  there is data on the card. It pulls the data off the card, packages it
  into a sk_buff and lets the kernel know the data is there for it by
  doing a netif_rx(sk_buff). You need to know how to enable interrupt
  generation upon Rx of data, how to check any relevant Rx status bits,
  and how to get that data off the card (again sh mem, PIO, DMA, etc.)

  8.3.5.  Open function

  linked to dev->open and called by the networking layers when somebody
  does ifconfig eth0 up - this puts the device on line and enables it
  for Rx/Tx of data. Any special initialization incantations that were
  not done in the probe sequence (enabling IRQ generation, etc.)  would
  go in here.

  8.3.6.  Close function (optional)

  This puts the card in a sane state when someone does ifconfig eth0
  down.  It should free the IRQs and DMA channels if the hardware
  permits, and turn off anything that will save power (like the
  transceiver).

  8.3.7.  Miscellaneous functions

  Things like a reset function, so that if things go south, the driver
  can try resetting the card as a last ditch effort.  Usually done when
  a Tx times out or similar. Also a function to read the statistics
  registers of the card if so equipped.

  8.4.  Interrupts and Linux

  There are two kinds of interrupt handlers in Linux: fast ones and slow
  ones. You decide what kind you are installing by the flags you pass to
  irqaction(). The fast ones, such as the serial interrupt handler, run
  with _all_ interrupts disabled. The normal interrupt handlers, such as
  the one for ethercard drivers, runs with other interrupts enabled.

  There is a two-level interrupt structure. The `fast' part handles the
  device register, removes the packets, and perhaps sets a flag.  After
  it is done, and interrupts are re-enabled, the slow part is run if the
  flag is set.

  The flag between the two parts is set by:

       mark_bh(INET_BH);

  Usually this flag is set within dev_rint() during a received-packet
  interrupt, and set directly by the device driver during a transmit-
  complete interrupt.

  You might wonder why all interrupt handlers cannot run in `normal
  mode' with other interrupts enabled. Ross Biro uses this scenario to
  illustrate the problem:

  ╖  You get a serial interrupt, and start processing it.  The serial
     interrupt is now masked.

  ╖  You get a network interrupt, and you start transferring a maximum-
     sized 1500 byte packet from the card.

  ╖  Another character comes in, but this time the interrupts are
     masked!

  The `fast' interrupt structure solves this problem by allowing
  bounded-time interrupt handlers to run without the risk of leaving
  their interrupt lines masked by another interrupt request.

  There is an additional distinction between fast and slow interrupt
  handlers -- the arguments passed to the handler. A `slow' handler is
  defined as

  ______________________________________________________________________

                  static void
                  handle_interrupt(int reg_ptr)
                  {
                      int irq = -(((struct pt_regs *)reg_ptr)->orig_eax+2);
                      struct device *dev = irq2dev_map[irq];
                  ...
  ______________________________________________________________________

  While a fast handler gets the interrupt number directly

  ______________________________________________________________________

                  static void
                  handle_fast_interrupt(int irq)
                  {
                  ...
  ______________________________________________________________________

  A final aspect of network performance is latency. The only board that
  really addresses this is the 3c509, which allows a predictive
  interrupt to be posted. It provides an interrupt response timer so
  that the driver can fine-tune how early an interrupt is generated.

  8.5.  Programming the Intel chips (i82586 and i82593)

  These chips are used on a number of cards, namely the 3c507 ('86), the
  Intel EtherExpress 16 ('86), Microdyne's exos205t ('86), the Z-Note
  ('93), and the Racal-Interlan ni5210 ('86).

  Russ Nelson writes: `Most boards based on the 82586 can reuse quite a
  bit of their code.  More, in fact, than the 8390-based adapters. There
  are only three differences between them:

  ╖  The code to get the Ethernet address,

  ╖  The code to trigger CA on the 82586, and

  ╖  The code to reset the 82586.

  The Intel EtherExpress 16 is an exception, as it I/O maps the 82586.
  Yes, I/O maps it. Fairly clunky, but it works.

  Garrett Wollman did an AT&T driver for BSD that uses the BSD
  copyright. The latest version I have (Sep '92) only uses a single
  transmit buffer. You can and should do better than this if you've got
  the memory. The AT&T and 3c507 adapters do; the ni5210 doesn't.

  The people at Intel gave me a very big clue on how you queue up
  multiple transmit packets. You set up a list of NOP-> XMIT-> NOP->
  XMIT-> NOP-> XMIT-> beginning) blocks, then you set the `next' pointer
  of all the NOP blocks to themselves. Now you start the command unit on
  this chain. It continually processes the first NOP block. To transmit
  a packet, you stuff it into the next transmit block, then point the
  NOP to it. To transmit the next packet, you stuff the next transmit
  block and point the previous NOP to it. In this way, you don't have to
  wait for the previous transmit to finish, you can queue up multiple
  packets without any ambiguity as to whether it got accepted, and you
  can avoid the command unit start-up delay.'

  8.6.  Technical information from 3Com

  If you are interested in working on drivers for 3Com cards, you can
  get technical documentation from 3Com. Cameron has been kind enough to
  tell us how to go about it below:

  3Com's Ethernet Adapters are documented for driver writers in our
  `Technical References' (TRs). These manuals describe the programmer
  interfaces to the boards but they don't talk about the diagnostics,
  installation programs, etc that end users can see.

  The Network Adapter Division marketing department has the TRs to give
  away. To keep this program efficient, we centralized it in a thing
  called `CardFacts.' CardFacts is an automated phone system. You call
  it with a touch-tone phone and it faxes you stuff. To get a TR, call
  CardFacts at 408-727-7021. Ask it for Developer's Order Form, document
  number 9070. Have your fax number ready when you call. Fill out the
  order form and fax it to 408-764-5004.  Manuals are shipped by Federal
  Express 2nd Day Service.

  After you get a manual, if you still can't figure out how to program
  the board, try our `CardBoard' BBS at 1-800-876-3266, and if you can't
  do that, write [e-mail] and ask him for alternatives.
  If you have a real stumper that nobody has figured out yet, the fellow
  who needs to know about it is [e-mail].

  There are people here who think we are too free with the manuals, and
  they are looking for evidence that the system is too expensive, or
  takes too much time and effort. That's why it's important to try to
  use CardFacts before you start calling and mailing the people I named
  here.

  There are even people who think we should be like Diamond and Xircom,
  requiring tight `partnership' with driver writers to prevent poorly
  performing drivers from getting written. So far, 3Com customers have
  been really good about this, and there's no problem with the level of
  requests we've been getting. We need your continued cooperation and
  restraint to keep it that way.

          Cameron Spitzer, 408-764-6339
          3Com NAD
          Santa Clara
          work: [e-mail]
          home: [e-mail]

  8.7.  Notes on AMD PCnet / LANCE Based cards

  The AMD LANCE (Local Area Network Controller for Ethernet) was the
  original offering, and has since been replaced by the `PCnet-ISA'
  chip, otherwise known as the 79C960.  A relatively new chip from AMD,
  the 79C960, is the heart of many new cards being released at present.
  Note that the name `LANCE' has stuck, and some people will refer to
  the new chip by the old name. Dave Roberts of the Network Products
  Division of AMD was kind enough to contribute the following
  information regarding this chip:
  `As for the architecture itself, AMD developed it originally and
  reduced it to a single chip -- the PCnet(tm)-ISA -- over a year ago.
  It's been selling like hotcakes ever since.

  Functionally, it is equivalent to a NE1500. The register set is
  identical to the old LANCE with the 1500/2100 architecture additions.
  Older 1500/2100 drivers will work on the PCnet-ISA.  The NE1500 and
  NE2100 architecture is basically the same.  Initially Novell called it
  the 2100, but then tried to distinguish between coax and 10BASE-T
  cards. Anything that was 10BASE-T only was to be numbered in the 1500
  range. That's the only difference.

  Many companies offer PCnet-ISA based products, including HP, Racal-
  Datacom, Allied Telesis, Boca Research, Kingston Technology, etc.  The
  cards are basically the same except that some manufacturers have added
  `jumperless' features that allow the card to be configured in
  software. Most have not. AMD offers a standard design package for a
  card that uses the PCnet-ISA and many manufacturers use our design
  without change.  What this means is that anybody who wants to write
  drivers for most PCnet-ISA based cards can just get the data-sheet
  from AMD. Call our literature distribution center at [phone] and
  ask for the Am79C960, PCnet-ISA data sheet. It's free.

  A quick way to understand whether the card is a `stock' card is to
  just look at it. If it's stock, it should just have one large chip on
  it, a crystal, a small IEEE address PROM, possibly a socket for a boot
  ROM, and a connector (1, 2, or 3, depending on the media options
  offered). Note that if it's a coax card, it will have some transceiver
  stuff built onto it as well, but that should be near the connector and
  away from the PCnet-ISA.'

  There is also some info regarding the LANCE chip in the file lance.c
  which is included in the standard kernel.

  A note to would-be card hackers is that different LANCE
  implementations do `restart' in different ways. Some pick up where
  they left off in the ring, and others start right from the beginning
  of the ring, as if just initialised. This is a concern when setting
  the multicast list.

  8.8.  Multicast and Promiscuous Mode

  Another one of the things Donald has worked on is implementing
  multicast and promiscuous mode hooks.  All of the released (i.e. not
  ALPHA) ISA drivers now support promiscuous mode.

  Donald writes: `At first I was planning to do it while implementing
  either the /dev/* or DDI interface, but that's not really the correct
  way to do it. We should only enable multicast or promiscuous modes
  when something wants to look at the packets, and shut it down when
  that application is finished, neither of which is strongly related to
  when the hardware is opened or released.

  I'll start by discussing promiscuous mode, which is conceptually easy
  to implement. For most hardware you only have to set a register bit,
  and from then on you get every packet on the wire. Well, it's almost
  that easy; for some hardware you have to shut the board (potentially
  dropping a few packet), reconfigure it, and then re-enable the
  ethercard. This is grungy and risky, but the alternative seems to be
  to have every application register before you open the ethercard at
  boot-time.

  OK, so that's easy, so I'll move on something that's not quite so
  obvious: Multicast. It can be done two ways:
  1. Use promiscuous mode, and a packet filter like the Berkeley packet
     filter (BPF). The BPF is a pattern matching stack language, where
     you write a program that picks out the addresses you are interested
     in. Its advantage is that it's very general and programmable. Its
     disadvantage is that there is no general way for the kernel to
     avoid turning on promiscuous mode and running every packet on the
     wire through every registered packet filter. See ``The Berkeley
     Packet Filter'' for more info.

  2. Using the built-in multicast filter that most etherchips have.

  I guess I should list what a few ethercards/chips provide:

          Chip/card  Promiscuous  Multicast filter
          ----------------------------------------
          Seeq8001/3c501  Yes     Binary filter (1)
          3Com/3c509      Yes     Binary filter (1)
          8390            Yes     Autodin II six bit hash (2) (3)
          LANCE           Yes     Autodin II six bit hash (2) (3)
          i82586          Yes     Hidden Autodin II six bit hash (2) (4)

  1. These cards claim to have a filter, but it's a simple yes/no
     `accept all multicast packets', or `accept no multicast packets'.

  2. AUTODIN II is the standard ethernet CRC (checksum) polynomial. In
     this scheme multicast addresses are hashed and looked up in a hash
     table. If the corresponding bit is enabled, this packet is
     accepted. Ethernet packets are laid out so that the hardware to do
     this is trivial -- you just latch six (usually) bits from the CRC
     circuit (needed anyway for error checking) after the first six
     octets (the destination address), and use them as an index into the
     hash table (six bits -- a 64-bit table).

  3. These chips use the six bit hash, and must have the table computed
     and loaded by the host. This means the kernel must include the CRC
     code.

  4. The 82586 uses the six bit hash internally, but it computes the
     hash table itself from a list of multicast addresses to accept.

  Note that none of these chips do perfect filtering, and we still need
  a middle-level module to do the final filtering. Also note that in
  every case we must keep a complete list of accepted multicast
  addresses to recompute the hash table when it changes.

  My first pass at device-level support is detailed in the outline
  driver skeleton.c

  It looks like the following:

  ______________________________________________________________________
          #ifdef HAVE_MULTICAST
          static void set_multicast_list(struct device *dev, int num_addrs,
                           void *addrs);
          #endif
          .
          .

          ethercard_open() {
          ...
          #ifdef HAVE_MULTICAST
                  dev->set_multicast_list = &set_multicast_list;
          #endif
          ...

          #ifdef HAVE_MULTICAST
          /* Set or clear the multicast filter for this adaptor.
             num_addrs -- -1      Promiscuous mode, receive all packets
             num_addrs -- 0       Normal mode, clear multicast list
             num_addrs > 0        Multicast mode, receive normal and
                  MC packets, and do best-effort filtering.
           */
          static void
          set_multicast_list(struct device *dev, int num_addrs, void *addrs)
          {
          ...
  ______________________________________________________________________

  Any comments, criticism, etc. are welcome.'

  8.9.  The Berkeley Packet Filter (BPF)

  The general idea of the developers is that the BPF functionality
  should not be provided by the kernel, but should be in a (hopefully
  little-used) compatibility library.

  For those not in the know: BPF (the Berkeley Packet Filter) is an
  mechanism for specifying to the kernel networking layers what packets
  you are interested in. It's implemented as a specialized stack
  language interpreter built into a low level of the networking code. An
  application passes a program written in this language to the kernel,
  and the kernel runs the program on each incoming packet. If the kernel
  has multiple BPF applications, each program is run on each packet.

  The problem is that it's difficult to deduce what kind of packets the
  application is really interested in from the packet filter program, so
  the general solution is to always run the filter. Imagine a program
  that registers a BPF program to pick up a low data-rate stream sent to
  a multicast address.  Most ethernet cards have a hardware multicast
  address filter implemented as a 64 entry hash table that ignores most
  unwanted multicast packets, so the capability exists to make this a
  very inexpensive operation. But with the BFP the kernel must switch
  the interface to promiscuous mode, receive _all_ packets, and run them
  through this filter. This is work, BTW, that's very difficult to
  account back to the process requesting the packets.

  9.  Networking with a Laptop/Notebook Computer

  There are currently only a few ways to put your laptop on a network.
  You can use the SLIP code (and run at serial line speeds); you can buy
  one of the few laptops that come with a NE2000-compatible ethercard;
  you can get a notebook with a supported PCMCIA slot built-in; you can
  get a laptop with a docking station and plug in an ISA ethercard; or
  you can use a parallel port Ethernet adapter such as the D-Link
  DE-600.

  9.1.  Using SLIP

  This is the cheapest solution, but by far the most difficult. Also,
  you will not get very high transmission rates. Since SLIP is not
  really related to ethernet cards, it will not be discussed further
  here. See the NET-2 Howto.

  9.2.  Built in NE2000

  This solution severely limits your laptop choices and is fairly
  expensive. Be sure to read the specifications carefully, as you may
  find that you will have to buy an additional non-standard transceiver
  to actually put the machine on a network. A good idea might be to boot
  the notebook with a kernel that has ne2000 support, and make sure it
  gets detected and works before you lay down your cash.

  9.3.  PCMCIA Support

  As this area of Linux development is fairly young, I'd suggest that
  you join the LAPTOPS mailing channel. See ``Mailing lists...''  which
  describes how to join a mailing list channel.

  Try and determine exactly what hardware you have (ie. card
  manufacturer, PCMCIA chip controller manufacturer) and then ask on the
  LAPTOPS channel. Regardless, don't expect things to be all that
  simple.  Expect to have to fiddle around a bit, and patch kernels,
  etc.  Maybe someday you will be able to type `make config' 8-)

  At present, the two PCMCIA chipsets that are supported are the
  Databook TCIC/2 and the intel i82365.

  There is a number of programs on tsx-11.mit.edu in
  /pub/linux/packages/laptops/ that you may find useful. These range
  from PCMCIA Ethercard drivers to programs that communicate with the
  PCMCIA controller chip. Note that these drivers are usually tied to a
  specific PCMCIA chip (ie. the intel 82365 or the TCIC/2)

  For NE2000 compatible cards, some people have had success with just
  configuring the card under DOS, and then booting linux from the DOS
  command prompt via loadlin.

  For those that are net-surfing you can try:

  Don's PCMCIA Stuff <http://cesdis.gsfc.nasa.gov/linux/pcmcia.html>

  Anyway, the PCMCIA driver problem isn't specific to the Linux world.
  It's been a real disaster in the MS-DOS world. In that world people
  expect the hardware to work if they just follow the manual.  They
  might not expect it to interoperate with any other hardware or
  software, or operate optimally, but they do expect that the software
  shipped with the product will function. Many PCMCIA adaptors don't
  even pass this test.

  Things are looking up for Linux users that want PCMCIA support, as
  substantial progress is being made. Pioneering this effort is David
  Hinds. His latest PCMCIA support package can be obtained from cb-
  iris.stanford.edu in the directory /pub/pcmcia/. Look for a file like
  pcmcia-cs-X.Y.Z.tgz where X.Y.Z will be the latest version number.
  This is most likely uploaded to tsx-11.mit.edu as well.

  Note that Donald's PCMCIA enabler works as a user-level process, and
  David Hinds' is a kernel-level solution.  You may be best served by
  David's package as it is much more widely used.

  9.4.  ISA Ethercard in the Docking Station.

  Docking stations for laptops typically cost about $250 and provide two
  full-size ISA slots, two serial and one parallel port. Most docking
  stations are powered off of the laptop's batteries, and a few allow
  adding extra batteries in the docking station if you use short ISA
  cards. You can add an inexpensive ethercard and enjoy full-speed
  ethernet performance.

  9.5.  Pocket / parallel port adaptors.

  The `pocket' ethernet adaptors may also fit your need.  Until recently
  they actually costed more than a docking station and cheap ethercard,
  and most tie you down with a wall-brick power supply.  At present, you
  can choose from the D-Link, or the RealTek adaptor.  Most other
  companies, especially Xircom, (see ``Xircom'') treat the programming
  information as a trade secret, so support will likely be slow in
  coming. (if ever!)

  Note that the transfer speed will not be all that great (perhaps
  100kB/s tops?) due to the limitations of the parallel port interface.

  See ``DE-600 / DE-620'' and ``RealTek'' for supported pocket adaptors.

  You can sometimes avoid the wall-brick with the adaptors by buying or
  making a cable that draws power from the laptop's keyboard port. (See
  ``keyboard power'')

  10.  Miscellaneous.

  Any other associated stuff that didn't fit in anywhere else gets
  dumped here. It may not be relevant, and it may not be of general
  interest but it is here anyway.

  10.1.  Passing Ethernet Arguments to the Kernel

  Here are two generic kernel commands  that can be passed to the kernel
  at boot time. This can be done with LILO, loadlin, or any other
  booting utility that accepts optional arguments.

  For example, if the command was `blah' and it expected 3 arguments
  (say 123, 456, and 789) then, with LILO, you would use:

  LILO: linux blah=123,456,789

  Note: PCI cards have their i/o and IRQ assigned by the BIOS at boot.
  This means that any boot time arguments for a PCI card's IRQ or i/o
  ports are usually ignored.

  For more information on (and a complete list of) boot time arguments,
  please see the BootPrompt-HOWTO
  <http://sunsite.unc.edu/mdw/HOWTO/BootPrompt-HOWTO.html>

  10.1.1.  The ether command

  In its most generic form, it looks something like this:

       ether=IRQ,BASE_ADDR,PARAM_1,PARAM_2,NAME

  All arguments are optional.  The first non-numeric argument is taken
  as the NAME.

  IRQ: Obvious.  An IRQ value of `0' (usually the default) means to
  autoIRQ.  It's a historical accident that the IRQ setting is first
  rather than the base_addr -- this will be fixed whenever something
  else changes.

  BASE_ADDR: Also obvious.  A value of `0' (usually the default) means
  to probe a card-type-specific address list for an ethercard.

  PARAM_1: It was orginally used as an override value for the memory
  start for a shared-memory ethercard, like the WD80*3.  Some drivers
  use the low four bits of this value to set the debug message level.  0
  -- default, 1-7 -- level 1..7, (7 is maximum verbosity)  8 -- level 0
  (no messages). Also, the LANCE driver uses the low four bits of this
  value to select the DMA channel.  Otherwise it uses auto-DMA.

  PARAM_2: The 3c503 driver uses this to select between the internal and
  external transceivers.  0 -- default/internal, 1 -- AUI external.  The
  Cabletron E21XX card also uses the low 4 bits of PARAM_2 to select the
  output media. Otherwise it detects automatically.

  NAME: Selects the network device the values refer to.  The standard
  kernel uses the names `eth0', `eth1', `eth2' and `eth3' for bus-
  attached ethercards, and `atp0' for the parallel port `pocket'
  ethernet adaptor. The arcnet driver uses `arc0' as its name.  The
  default setting is for a single ethercard to be probed for as `eth0'.
  Multiple cards can only be enabled by explicitly setting up their base
  address using these LILO parameters.  The 1.0 kernel has LANCE-based
  ethercards as a special case.  LILO arguments are ignored, and LANCE
  cards are always assigned `eth<n>' names starting at `eth0'.
  Additional non-LANCE ethercards must be explicitly assigned to
  `eth<n+1>', and the usual `eth0' probe disabled with something like
  `ether=0,-1,eth0'.  ( Yes, this is bug. )

  10.1.2.  The reserve command

  This next lilo command is used just like `ether=' above, ie. it is
  appended to the name of the boot select specified in lilo.conf

       reserve=IO-base,extent{,IO-base,extent...}

  In some machines it may be necessary to prevent device drivers from
  checking for devices (auto-probing) in a specific region. This may be
  because of poorly designed hardware that causes the boot to freeze
  (such as some ethercards), hardware that is mistakenly identified,
  hardware whose state is changed by an earlier probe, or merely
  hardware you don't want the kernel to initialize.

  The reserve boot-time argument addresses this problem by specifying an
  I/O port region that shouldn't be probed. That region is reserved in
  the kernel's port registration table as if a device has already been
  found in that region. Note that this mechanism shouldn't be necessary
  on most machines. Only when there is a problem or special case would
  it be necessary to use this.

  The I/O ports in the specified region are protected against device
  probes. This was put in to be used when some driver was hanging on a
  NE2000, or misidentifying some other device as its own.  A correct
  device driver shouldn't probe a reserved region, unless another boot
  argument explicitly specifies that it do so.  This implies that
  reserve will most often be used with some other boot argument. Hence
  if you specify a reserve region to protect a specific device, you must
  generally specify an explicit probe for that device. Most drivers
  ignore the port registration table if they are given an explicit
  address.

  For example, the boot line

       LILO: linux  reserve=0x300,32  ether=0,0x300,eth0

  keeps all device drivers except the ethercard drivers from probing
  0x300-0x31f.

  As usual with boot-time specifiers there is an 11 parameter limit,
  thus you can only specify 5 reserved regions per reserve keyword.
  Multiple reserve specifiers will work if you have an unusually
  complicated request.

  10.2.  Using the Ethernet Drivers as Modules

  At present, all the modules are put in the subdirectory modules in
  your Linux kernel source tree (usually in the form of symbolic links).
  To actually generate the modules, you have to type make modules after
  you have finished building the kernel proper. Earlier kernels built
  them automatically, which wasn't fair to those compiling on 4MB
  386sx-16 machines.

  Most modules accept parameters like io=0x340 and irq=12 on the insmod
  command line. It is STRONGLY ADVISED that you supply these parameters
  to avoid probing for the card. Unlike PCI and EISA devices, there is
  no real safe way to do auto-probing for ISA devices, and so it should
  be avoided when using drivers as modules.

  A list of all the parameters that each module accepts can be found in
  the file:

  /usr/src/linux/Documentation/networking/net-modules.txt

  It is recommended that you read that to find out what options you can
  use for your particular card.

  Once you have figured out the arguments/options you are going to use,
  you can insert the module by typing as root:

  ______________________________________________________________________
          insmod mod_name.o [io=val1[,val2,...]] [irq=val7[,val8,...]]
  ______________________________________________________________________

  The comma separated value lists are used for modules that have the
  capability to handle multiple devices from a single module, such as
  all the 8390 drivers, and the PLIP driver.

  See the insmod(8) manual page for information on passing arguments to
  the module as it is being loaded.  The command lsmod will show you
  what modules are loaded, and rmmod will remove them.

  Once a module is inserted, then you can use it just like normal, and
  give ifconfig commands. If you set up your networking at boot, then
  make sure your /etc/rc* files run the insmod command(s) before getting
  to the ifconfig command.

  Also note that a busy module can't be removed. That means that you
  will have to ifconfig eth0 down  (shut down the ethernet card) before
  you can remove the module(s).

  10.2.1.  8390 Based Cards as Modules

  The present list of 8390 based drivers is: 3c503, ac3200, e2100, hp,
  hp-plus, ne, smc-ultra and wd. These cards were not supported as
  modules for kernel versions prior to 1.3.42.  (This does not include
  some of the separately distributed PCMCIA drivers (e.g. de-650) that
  are also 8390 based, that have had module support for quite some time
  now.)

  If you have an 8390 based card, you may have to insert two modules,
  8390.o and then the module for your card.  If 8390 support has been
  built into your kernel, then you will not need to insert the 8390
  module. (8390 support is built in whenever an 8390 based card is
  selected to be built into the kernel.) Doing a cat /proc/ksyms | grep
  8390 will tell you if 8390 support is in your kernel.

  For an 8390 based card, you will have to remove the card module before
  removing the 8390 module, as the 8390 module is used by the card
  module, and thus marked as busy.

  The 8390 series of network drivers now support multiple card systems
  without reloading the same module multiple times (memory efficient!)
  This is done by specifying multiple comma separated values, such as:

  ______________________________________________________________________
          insmod 3c503.o io=0x280,0x300,0x330,0x350 xcvr=0,1,0,1
  ______________________________________________________________________

  The above would have the one module controlling four 3c503 cards, with
  card 2 and 4 using external transcievers.

  It is *STRONGLY RECOMMENDED* that you supply "io=" instead of
  autoprobing.  If an "io=" argument is not supplied, then the ISA 8390
  drivers will complain about autoprobing being not recommended, and
  begrudgingly autoprobe for a *SINGLE CARD ONLY* -- if you want to use
  multiple cards you *have* to supply an "io=0xNNN,0xQQQ,..." argument.

  The ne module is an exception to the above. A NE2000 is essentially an
  8390 chip, some bus glue and some RAM.  Because of this, the ne probe
  is more invasive than the rest, and so at boot we make sure the ne
  probe is done last of all the 8390 cards (so that it won't trip over
  other 8390 based cards) With modules we can't ensure that all other
  non-ne 8390 cards have already been found. Because of this, the ne
  module REQUIRES an io=0xNNN argument passed in via insmod. It will
  refuse to autoprobe.

  It is also worth noting that auto-IRQ probably isn't as reliable
  during the flurry of interrupt activity on a running machine. Cards
  such as the ne2000 that can't get the IRQ setting from an EEPROM or
  configuration register are probably best supplied with an irq=M
  argument as well. The file

  /usr/src/linux/Documentation/networking/net-modules.txt

  also lists how the interrupt settings are determined for the various
  cards if an irq=N value is not given.

  10.3.  Mailing Lists and the Linux Newsgroups

  If you have questions about your ethernet card, please READ this
  document first. You may also want to join the NET channel of the Linux
  mailing lists by sending mail to [e-mail] to get
  help with what lists are available, and how to join them.

  Furthermore keep in mind that the NET channel is for development
  discussions only. General questions on how to configure your system
  should be directed to comp.os.linux.setup unless you are actively
  involved in the development of part of the networking for Linux.  We
  ask that you please respect this general guideline for content.

  Also, the news groups comp.sys.ibm.pc.hardware.networking and
  comp.dcom.lans.ethernet should be used for questions that are not
  Linux specific.

  10.4.  Related Documentation

  Much of this info came from saved postings from the comp.os.linux
  groups, which shows that it is a valuable resource of information.
  Other useful information came from a bunch of small files by Donald
  himself. Of course, if you are setting up an Ethernet card, then you
  will want to read the NET-2 Howto so that you can actually configure
  the software you will use.  Also, if you fancy yourself as a bit of a
  hacker, you can always scrounge some additional info from the driver
  source files as well. There is usually a paragraph or two in there
  describing any important points before any actual code starts..

  For those looking for information that is not specific in any way to
  Linux (i.e. what is 10BaseT, what is AUI, what does a hub do, etc.)  I
  strongly recommend the Ethernet-FAQ  that is posted regularly to the
  newsgroup comp.dcom.lans.ethernet.  You can grab it from the following
  URL:

  Ethernet FAQ
  <ftp://dorm.rutgers.edu/pub/novell/info_and_docs/Ethernet.FAQ>

  You can also have a look at the `Ethernet-HomePage' so to speak, which
  is at the following URL:

  Ethernet-HomePage <http://wwwhost.ots.utexas.edu/ethernet/ethernet-
  home.html>

  10.5.  Contributors

  Other people who have contributed (directly or indirectly) to the
  Ethernet-Howto are, in alphabetical order:

          Ross Biro               <[e-mail]>
          Alan Cox                <[e-mail]>
          David C. Davies         <[e-mail]>
          Bjorn Ekwall            <[e-mail]>
          David Hinds             <[e-mail]>
          Michael Hipp            <[e-mail]>
          Mike Jagdis             <[e-mail]>
          Duke Kamstra            <[e-mail]>
          Russell Nelson          <[e-mail]>
          Cameron Spitzer         <[e-mail]>
          Dave Roberts            <[e-mail]>
          Glenn Talbott           <[e-mail]>

  Many thanks to the above people, and all the other unmentioned testers
  out there.

  10.6.  Closing

  If you have found any glaring typos, or outdated info in this
  document, please let one of us know. It's getting big, and it is easy
  to overlook stuff.

  Thanks,

  Paul Gortmaker, [e-mail]

  Donald J. Becker, [e-mail]