Danny Amor's Online Library/Danny Amor's Online Library - Volume 1.iso/html/faqs/faq/386bsd-faq/part7

Text File | 1995-07-25 | 29.9 KB | 702 lines

Subject: [comp.os.386bsd] BNR/2 derived BSD for PCs FAQ (Part 7 of 10)
Newsgroups: comp.os.386bsd.announce,comp.answers,news.answers
From: [e-mail] (Dave Burgess)
Date: 13 Nov 1994 10:41:53 -0600

Posted-By: auto-faq 3.1.1.2
Archive-name: 386bsd-faq/part7

Section 6.    (Interaction with MS-DOS)

6.0    Working with DOS and BNR/2 related software.

    This section is designed to cover some of the more common
    problems that DOS will have when interacting with BNR/2.
    There are other sections of the FAQ that deal with
    indirectly with this .  Try looking in sections 0, 1, and 2
    to see if something in there (particularly when talking
    about DOS and *BSD coexisting on a single drive).


6.1    Formatting a floppy

    There is a rumor that floppy formatting either is possible or was
    possible at one time.  If you see any software or FTP sites with
    anything about this, please contact [e-mail]
    and I will make sure it gets updated in here.

    There was a set of patches that were developed to allow floppy
    formatting.  They are not currently included in any of the *BSD
    systems.

    I have actually applied the patches for floppy formatting here
    on an older version of NetBSD, and they seem to work just fine.
    The fdformat program could use some work, but seems to work OK.
    According to the author, similar patches are available for
    FreeBSD and the original 386BSD.  The package that I used here
    was posted in comp.os.386bsd.* somewhere.  I think that it is
    available by anonymous FTP from cynjut.infonet.net.  If not,
    E-Mail me at [e-mail] and I will mail you a
    tar file with the stuff that I have available.


6.2    Sharing the Disk with MS-DOS

    There are a myriad of questions about how to share a disk between
    386bsd and MS-DOS.  They all boils down to one of the <n> following
    questions:

    1)  How can I partition my drive for both MS-DOS and 386bsd?
    2)  I can install using the whole disk, but I can't install when
    I try to share the drive between 386bsd and MS-DOS.  Why?
    3)  I can use either MS-DOS or 386BSD on my hard drive,
    but shutdown -todos doesn't seem to work.


6.2.1    How can I partition my drive to support both MS-DOS and *bsd?

    NOTE:  Before attempting to install *bsd on a computer with an
    active DOS partition, ALWAYS back up your hard drive.  No one on
    the net, no matter how talented, can help you recover a hosed
    MS-DOS file system.  If you lose all of your data, it is YOUR
    fault.

    During the install phase, you need to have un-allocated space left
    on your disk drive.  This allows the install program to correctly
    install the *bsd partition in the partition table and DOS to
    peacefully co-exist with *bsd.

    If you do not have any space available on your hard drive, you will
    not be able to install both.  Re-fdisk your hard drive and make
    sure you have left un-allocated space in the partition table.
    This WILL wipe out your DOS partition - Permanently.

    Even though the partition table procedure above may have worked,
    there are still no guarantees that your system will boot after
    the install.  This problem most often manifests itself as one of
    the endless reboot problems.  You would normally be able to boot
    DOS from the hard disk, but not *bsd (once that partition is
    marked as active).

    Once the partition table has been correctly defined with both
    DOS and *bsd, there can still be problem.  One of the most
    common is that the disk drive works in some sort of translation
    mode.  This is particularly common with drives that physically have
    more than 1024 cylinders.  DOS cannot access a drive with more than
    1024 cylinders.  Translation mode will have to be turned off, usually
    by redefining your hard drive in SETUP as one of the user definable
    types.  This change will normally trash your hard drive, or at least
    render your DOS partition unreadable.

    The solution to this problem is to install *bsd at the end of the
    hard drive.  While DOS cannot use cylinders above 1024, *bsd has
    no such limitations, once it has booted.  During the boot-up phase,
    some of the newer boot blocks will refer to the BIOS for some
    services.  Specifically, the disk is checked for a bad sector map
    on the last track.  Since the BIOS cannot deal with cylinders
    higher than 1024, your bad sector map will be incorrectly
    identified as 1023 if the number of cylinders is larger than that.
    This problem is being worked on, and I hope to change this section
    with better news later.

    NOTE:  The only people that this problem will effect are those
    MFM and ESDI users that have drives with more than 1023 tracks.
    While drives of this type are not the overwhelming majority,
    neither are they an anomoly.  People are working on it.

    As an example, if your hard disk physically has 8 heads, 16 sectors
    per track, and 2000 cylinders (128M); you MUST use some sort of disk
    translation in order to use the entire drive.  An obvious geometry
    for this drive (for DOS) would be 16 heads, 16 sectors, and 1000
    cylinders.  Unfortunately, *bsd operates using the disk drives
    native geometry as reported during the probe phase of boot up.  This
    will probably be 8/16/2000, and will NOT agree with your translated
    disk geometry.  This causes an endless reboot cycle.  If you change
    the geometry so that the drive agrees with the disklabel, your DOS
    partition is toast.

    The best way to operate in this case would be to (for example)
    split the disk in half.  That leaves 64M for DOS, using a
    geometry of 8 heads, 16 sectors per track, and the first 1000
    cylinders for DOS.  The second 1000 cylinders could then safely
    be used for *bsd.  The DOS partition table may even be capable of
    showing this partition as it actually exists.

        ACCESSING MS-DOS PARTITIONS FROM NetBSD-i386

    First off, it's important to understand BSD disklabels.  The
    disklabel is a description of the Unix parition layout and other
    disk parameters stored on-disk, usually somewhere in the first
    couple of sectors.  There is a maximum of 8 partitions, labelled
    "a" thru "h".  Typically partition "a" is assigned to the root
    partition, partition "b" is configured as a swap area, and
    partition "c" is defined as the whole disk.  You can change these,
    but it's a good idea to stick with this scheme, as many programs
    assume that's the way things are going to be.

    If you're whole disk is dedicated to Unix, then that's all you
    need to know.  But if you're sharing your disk with DOS, then
    there are a few magical things happening.

    DOS has it's own partitioning scheme.  The way NetBSD co-exists
    with this is to fit all of the Unix partitions into one DOS
    partition.  So partitions a-h all fit inside one DOS partition,
    which has a partition type of 165 (each MS-DOS partition has a
    "partition type" associated with it.  The BSD partition type is
    165).  In this setup, partition "c" refers to the entire BSD
    partition.  But in this scheme, partition "d" refers to the ENTIRE
    disk, MS-DOS partitions and all.

    So, if you want to access your MS-DOS partition from NetBSD, first
    you'll have to create a partition that points to the MS-DOS
    partition.  You'll want to run the command:

    disklabel -e -r /dev/r??0d    (fill in with your disk type).

    You'll get popped into an editor with all the disklabel stuff in
    it.  Go down to the bottom.  You should see something like:

    6 partitions:
    #        size   offset    fstype   [fsize bsize   cpg]
      a:    30720   409600    4.2BSD     1024  8192    16   # (Cyl...
      b:   129024   440320      swap                        # (Cyl...
      c:  1617920   409600    unused        0     0         # (Cyl...
      d:  2029568        0    unused        0     0         # (Cyl...
      e:    61440   569344    4.2BSD     1024  8192    16   # (Cyl...
      f:  1396736   630784    4.2BSD     1024  8192    16   # (Cyl...

    (or whatever it appropriate for your disk).  Note that partition
    "a" starts on cylinder 200.  That's where my BSD partition starts
    on my disk.  Also note that partition "c" starts at 200 as well
    and goes to the end of the disk.  You'll also note that partition
    "d" goes from sector 0 all the way to the end of the disk.

    Add a new line that looks something like:

      g:   409568       32    MS-DOS                        # (Cyl.    0*- 199*)

    (The comment on the end isn't necessary.  Only the partition
    letter, size, offset, and parition type are needed.  You can
    put unused in instead of MS-DOS if you want).

    *NOTE* Be sure to change the line that says "6 partitions" to the
    new number of paritions that you have!!!  Otherwise you'll get an
    obscure error.  In my case I'd change that line to be "7 partitions".
    If you aren't sure what your MS-DOS partition size and offsets are,
    you can use the NetBSD fdisk to find them out.  Don't forget that
    there's a maximum of 8 partitions.

    Once you do that and you have MSDOSFS configured into your kernel,
    you can just do something like "mount -t msdos /dev/sd0g /msdos".
    Or you can put a line like this in your fstab:

    /dev/sd0g /msdos msdos rw 0 0

    If you want to access a DOS-only HD from NetBSD, here are some
    instructions posted by Charles Hannum a while back.  I haven't
    tried them myself, but they seem like they would work.

    Assuming you don't have something (like OS-BS) which uses the extra
    sectors in the boot track, you can do the following:

    1) Use the NetBSD `fdisk' or DOS `pfdisk' to create a NetBSD
    partition in the MBR which spans the entire disk.

    2) Save a copy of the MBR:

        dd if=/dev/rsd0d of=my-mbr bs=1b count=1

    3) Use `disklabel' to create a NetBSD label with the DOS partition
    and whatnot.  Answer `y' when it asks you if you want to `overwrite
    [a] disk with [a] DOS partition table'.

    4) Put back the saved copy of the MBR:

        dd if=my-mbr of=/dev/rsd0d bs=1b count=1

    This works for me.  Your milage may vary.

    Luke Mewburn <[e-mail]> has provided the following tutorial on
    using the pfdisk program and making your *bsd/NetBSD partitions
    peacefully coexist with DOS.  While this is kind of a 'cookbook'
    approach, please keep in mind that this is probably easily
    transferrable to all BNR derived Unices.


            Getting NetBSD 0.8 to coexist with DOS.

            Written 930510 by Luke Mewburn <[e-mail]>


    NetBSD can be made to happily co-exist with DOS if its install
    program knows how to modify the partition table. This assumes
    that you have access to a program which enables you to edit the
    partition table of your hard drive (such as Norton Utilities, or
    pfdisk).

    When you partition your hard drive, you will probably have a large
    partition in which you wish to place NetBSD. This has to have the
    partition ID of 165d (or 0xA5). To change this, you can use the
    'Partition Edit' section of Norton's, or you can use pfdisk.
    This document will go into more detail on how to use pfdisk, as it's
    freely available.

    I'll use my personal drive specifications in the following example.
    It is a 1001 cylinder, 15 trk/cyl, 17 sec/trk, 125MB drive. I
    low-level formatted it, and used fdisk on a MS-DOS 5.0 boot disk to
    create a primary partition '1' of 32MB, and an extended partition '2'
    of 93MB.  I formatted the drive with format c: /s to give myself a
    bootstrap for DOS (much faster than floppies :), but this isn't that
    necessary. Now, the next stage...

    Running pfdisk 0 (to access my first (and only :) HD) came up with
    something like:

    For help, enter: '?'
    pfdisk>

    At the prompt, enter 'l' to list partitions, giving (in my case),
    something like:

    # Partition table on device: 0
    geometry 1000 15 17 (cyls heads sectors)
    #  ID  First(cyl)  Last(cyl)  Name  # start, length (sectors)
    1   4      0        256       DOS16 # 17, 65518
    2   0    257        999       unkno # 65535, 189465
    3   0      0          0       empty # 0, 0
    4   0      0          0       empty # 0, 0
    active: 0 (none)

    (Note that there is 1 cylinder less - the last one is, I think,
    for the IDE controller to use when auto-mapping dud sectors out.)

    Now, we want to change the type of #2 (the prospective NetBSD
    partition) to 165. You can obtain a list of known IDs by selecting
    'I'. Depending on the version of pfdisk you have, 165 may or may not
    be known. This doesn't matter too much either way. To get the NetBSD
    install program to use the 2nd partition, I would enter:

    pfdisk> 2 165 257 999

    Another 'l' to list partitions would show that the entry for
    partition 2 will either look like one of the following (depending
    on whether pfdisk knows about the 386bsd partition type or not):

    2 165    257        999       unkno # 65535, 189465
    or
    2 165    257        999       386BS # 65535, 189465


    You could set the active partition with 'a 2' if you want NetBSD
    to always boot, but I personally recommend that you obtain a copy
    of OS-BS 1.35 or BOOTEASY to save you the hassle of running fdisk
    or pfdisk every time you wish to swap system types.

    To complete everything off, do 'w' to write out the info (once
    you're sure it's correct! :), and 'q' to quit the program.


    Well, I hope that is useful to someone. Comments can be directed
    to the author (Email: <[e-mail]>).


6.2.2    I can install using the whole disk, but I can't install when
    I try to share the drive between 386bsd and MS-DOS.  Why?

    This is an extension of the question above.  The most common reason
    for this is, once again, disk translation problems.  If the
    disklabel does not agree with the disk geometry, the install will
    fail.  Other incarnations of this problem are that you can install
    DOS, then 386bsd, and DOS will be hosed, or vice versa.

    There are more than a couple of people who will blithely suggest that
    this is a good thing, and you should install 386bsd exclusively,
    job not withstanding.


6.2.3    I can use either MS-DOS or 386BSD on my hard drive,
    but shutdown -todos doesn't seem to work.

    There is a known bug in shutdown that prevents the -todos option
    from working as advertised on all but the smallest DOS partitions.
    Many people have reported some success while using a very small
    (less than 32M) DOS partition as the first partition.

    There is a utility available for 386bsd which operates very much
    like the MS-DOS fdisk partitioning program.  You can use this program
    to mark the DOS partition active from 386bsd.  A similar procedure
    is used (fdisk in DOS) to mark the 386bsd partition as the active
    boot partition.  Boot managers are also an excellent investment for
    those individuals that need to boot both DOS and 386BSD.


6.2.4    Is there any hope of ever running MS-DOS applications under any of
    the free BSD systems?

    There is currently a project in development to port the Windows
    program exvironment to Linux and the *BSD systems.  Here is an
    excerpt from the original message announcing the project:

    As many of you already know, we are in the process of creating a
    Windows emulator.  This emulator is similar to Sun's Wabi product,
    but is being developed completely independent of them.  Many of
    you are anxious to hear the latest status of the project.  I have
    created a mailing list for those of you.  To join the list, simply
    send mail to:

    [e-mail]

    If your mailing address is not easy to deduce from the mail
    headers, then place the following line in the body of the message
    that you send.

    Reply-To: youraddress@yourmachine

    where youraddress@yourmachine should be replaced by your actual
    mailing address.


6.3    Accessing the MS-DOS filesystem

    One of the most common MS-DOS related questions (with the possible
    exception of 6.2 above) is how to access the DOS disk partitions
    from 386bsd.  One way is to modify mtools so that it recognizes your
    DOS partition.  This solution is provided by Jim Paradis
    ([e-mail]):

    --------------------------------------------------------------------
    To build a /usr/othersrc/public/mtools.2.0.5/devices.c file that
    lets you access the DOS partition, you need to know the byte offset
    of the DOS partition from the start of the hard disk.  You would then
    add an entry to the devices[] array as follows:

    {'C', "/dev/wd0d", <byte-offset>L, 16, 0, (int (*) ()) 0, 0, 0, 0},

    So, f'rinstance, if your DOS partition starts at the beginning of
    the disk, you'd have:

    {'C', "/dev/wd0d", 0L, 16, 0, (int (*) ()) 0, 0, 0, 0},

    On the other hand, if your DOS partition starts 32MB into the disk,
    you'd say something like:

    {'C', "/dev/wd0d", (32768L * 1024L), 16, 0, (int (*) ()) 0, 0, 0, 0},

    --------------------------------------------------------------------
    Of course, this is both the hard and VERY non-portable way of
    solving this problem.  An easier way would be to add PCFS or
    MSDOSFS to your *BSD system.  Both the PC File system and PC
    Network File System (PC-NFS) code has been ported to 386bsd/
    NetBSD/FreeBSD.  These are available from several sources,
    including the patchkit and in the -current trees.

    The instructions for using PCFS with 386BSD are provided by Scott
    Miles <[e-mail]>.

        What would probably be easier would be to add a partition to
        the disklabel for your DOS drive and then just mount it with
        PCFS.  I don't know if it's in the FAQ now, I haven't read it
        for a while, but this is what I did:

        1) run 'fdisk' and write down the DOS partition info for
        the start and size that it gives you.

        2) disklabel -e -r /dev/<raw device>
              - Add 1 to the '# partitions:', and then add another line
              for the DOS partition .  Mine went in after e: as

       f:   130977     63   unused      0     0     # (Cyl.    0*- 129*)

    (Ed.Note:  The unused should be something else, although I really
        couldn't tell you what. MSDOS is a recognized partition
        type name; maybe that should be used.  Also, make sure that
        your c: and d: partitions do not overlap this area.  h: might
        be a better partition letter to use; that way the MSDOS
        partition is graphically separate from the rest of the BSD
        partitions.  DO NOT USE a:, b:, c:, or d: for your DOS
        partition.  These are RESERVED for your BSD system and any
        attempt to use these for anything but what BSD uses them for
        will result in a completely hosed, totally dead, absolutely
        screwed up file system.  You have been warned! )

        3) Add a line to /etc/fstab if you want it mounted
        automatically.
             Mine is:
             /dev/wd0f   /dos      pcfs  rw   1       2

           Otherwise, just mount -t pcfs /dev/<part> /<dir>

    Mount has other options that may improve performance or increase
    security for your system.  See 'man mount' for more information
    about mounting your system read-only and other advanced features.

    In addition to this, Jordan Hubbard has provided us with the
    following description for mounting the DOS partition specifically
    from FreeBSD:

        How to mount your DOS partition from FreeBSD

    1. First, be root.  The following won't work as an ordinary user.

    2. Second, use 'fdisk' to see where your DOS partition starts.
    It will be labeled as type DOS.  On my system, 'fdisk /dev/sd0d'
    produces the following:

        ... (extraneous output, not of interest) ...
    The data for partition 0 is:
    sysid 6,(Primary 'big' DOS (> 32MB))
        start 32, size 306400 (149 Meg), flag 0
            beg: cyl 0/ sector 1/ head 1;
            end: cyl 149/ sector 32/ head 39

        This shows me that my DOS partition starts at sector 32, and
    is 306400 (512 byte) sectors long.

    NOTE:  If you're trying to mount a DOS `EXTENDED' partition, then
    you need to add `32' to this start address you got from fdisk in
    subsequent calculations, I.E. in the above example (assuming it
    was an EXTENDED partition rather than the Primary), you'd use
    `start 64, size 306400'.

    [Ed.Note.  This example assumes a SCSI disk.  For disks with a
    number of sectors per track which is different than 32, you will
    probably see the 32s above replaced with your number of sectors
    per track. ]

    3. Next, using this information, you craft a new disk entry in your
       /etc/disktab file that assigns one of your unused "UNIX"
       partitions to this DOS region.  Again, using my system as a
       default, you see I've created:

    disk0|DEC 5501:\
        :ty=winchester:dt=SCSI:se#512:nt#8:ns#256:nc#1001:rm#3600:\
        :pa#956416:oa#307200:ba#8192:fa#1024:ta=4.2BSD:\
        :pb#131072:ob#1263616:tb=swap:\
        :pc#1087488:oc#307200:tc=UNUSED:\
        :pe#306400:oe#32:te=MSDOS:

       As you can see, partition 'e' now points to the DOS partition as
       pointed out by fdisk.

       [Ed.Note again.  Remember what I said about the 32 above...]


    4. Now we have to actually stick the label on the disk, which is done
       with disklabel.  Using my example, this would be:

        disklabel -r -w sd0 disk0 SCSI /usr/mdec/sdboot /usr/mdec/bootsd

    5. Reboot your system to see the new disk label.

    6. Mount the DOS partition.  I do:

        mount -t pcfs /dev/sd0e /dos_c

       Where /dos_c is just a convenient directory to mount it.

    7. You're set!

    With the exception that the '-t' option is msdos in NetBSD, these
    instructions seem to work with the same facility for NetBSD.  I
    also received a note a couple of weeks ago (that I promptly deleted
    because I new that I would remember what it said) that DOS extended
    partitions are readable if you skip the first 'n' blocks in your
    computations (where 'n' is your number of sectors per track).  This
    way, you skip over the 'new' part of the DOS file system.  That means
    that insted of the oe:32 above, you would need an oe:48 instead.

    Also remember that the compressed file system in DOS 6 will probably
    be completely greek to your NetBSD/FreeBSD system.  I seriuosly
    doubt that you will be able to read the compressed DOS file system
    anytime in the forseeable future.


6.4    NFS/PC-NFS support

    The problems normally associated with PC-NFS are also associated
    with NFS in general.


6.4.1    Can I use 8K packets for NFS?  When I try, I have all kinds of
    problems.

    In addition to the NE2000 card, this problem can also manifest
    itself on other ISA networks cards that have a limited amount of
    memory.  Ken Raeburn ([e-mail]) has identified
    a common problem with the NE2000 card and provided us with a work
    around:

    --------------------------------------------------------------------
    I reported previously that I was seeing problems reading files over
    NFS using the ne2000 driver; timeouts would eventually be reported, no
    data would be read.  Listing files and directories (small ones
    anyway) were not a problem.

    After playing with etherfind and kernel printfs, I've come to this
    conclusion: Fragmented 8K UDP packets from the NFS server are not
    reaching the UDP layer in 386bsd.  The Sun is sending them (according
    to another Sun spying on the network), but the UDP input routine is
    never called.  I don't know if the bug here is on the 386bsd or Sun
    side, and won't have time to look into it in the next couple of days.

    In the meantime, mounting NFS file systems with "rsize=1024" does get
    rid of this problem.

    Ken
    --------------------------------------------------------------------

    As a matter of policy, specifying "rsize=1024,wsize=1024" works very
    well also, and makes the transfers seem to run faster.  This is
    probably because there are fewer collisions.  The disadvantage of
    this method comes from the kernel 'sync'ing after all NFS writes.
    This can slow NFS accesses considerably.  As with most
    generalizations, this one too can do nearly as much harm as good.
    Charles Hannum reports that he has no trouble using the default 8K
    packet size.  If you have trouble, reduce your default packet size
    until the problem goes away.

    WIth the newer drivers (especially the ed driver) most of these
    problems are solved automagically.  If you are still using the
    original 386bsd 0.1 release, you REALLY need to upgrade.


6.4.2    How do I get around the NFS "Permission denied" error?

    The problem is not the configuration of the server (unless there is
    no real requirement to run it in "secure" mode, and you happen to
    be running it that way anyway).  The problem is the fact that,
    even though mount request are sent on a privileged port, NFS
    connections are not.  This is part of secure NFS, and is not
    supported in 386BSD.


6.4.3    What does the message "BAD MNT RPC: RPC Authentication error;
    why = Invalid client credential" mean when I try to mount something
    from another machine?

    Hellmuth Michaelis ([e-mail]) offers the solution to this
    relatively common problem:

    You have to make sure that the user "root" is not present in more
    than 8 entries in the "/etc/group" - file on the 386BSD machine.
    Simply remove some entries and the NFS mounts will succeed.

    The problem is also explained in the Clarkson Driver documentation.
    On 386bsd, the maximum number of groups that can be associated with
    a particular user is specified in the source (in a #DEFINE).  In
    386bsd, this number is set to 8.  So, you actually have two routes
    you can take to correct this problem.  The first is outlined by
    Hellmuth, above, and the second is to edit and recompile the NSF
    software to allow more groups.


6.4.4    What does the message "Bad MNT RPC: RPC: Authentication error;
    why = Client credential too weak" mean when I try to mount something
    from another machine?

    This problem is a standard NFS problem; it simply means that your
    user number is not one of the ones that can mount this NFS.
    Normally, you will get this message when you are trying to mount
    a filesystem from a machine that allows 'root' to mount an NFS,
    but limits other users.


6.4.5    I get a lot of 'ring buffer overflow' messages using NFS and the
    ed0 driver.  Is there a problem?

    David Greenman ([e-mail]), the original author of
    the ed0 driver, provides us with some insight into the inner
    workings of the ed0 driver.

       It always surpises me that people don't just ask the original
    author these questions. :-) Anyway, the reason these are happening
    is that the access to the 8bit boards shared memory simply isn't
    fast enough to deal with full wire speeds...but the driver tries
    hard...so even though packets get dropped, your performance only
    drops to about what the ethernet board is capable of (should be
    in the 400-600k range with an 8bit card). NFS is especially bad
    because the UDP window is quite large (40k last time I looked),
    so the overflow condition can happen easily. I've explained this
    for the most part in the release notes for the driver, but these
    didn't make it into either the FreeBSD or NetBSD releases (we
    couldn't find an appropriate place to put them).

    >From the release notes:

    receive
    -------
       The 8390 implements a shared memory ring-buffer to store
    incoming packets.  The 8bit boards (3c503, and 8003) usually have
    only 8k bytes of shared memory.  This is only enough room for about
    4 full size (1500 byte) packets. This can sometimes be a problem,
    especially on the original WD8003E and 3c503.  This is because these
    boards' shared memory access speed is also quite slow compared to
    newer boards - typically only about 1MB/second. The additional
    overhead of this slow memory access, and the fact that there is
    only room for 4 full-sized packets means that the ring-buffer
    will occassionally overflow.  When this happens, the board must
    be reset to avoid a lockup problem in early revision 8390's.
    Resetting the board will cause all of the data in the ring-buffer
    to be lost - requiring it to be re-transmitted/received...slowing
    things even further.  Because of these problems, maximum throughput
    on boards of this type is only about 400-600k per second. The 16bit
    boards (8013 series), however, have 16k of memory as well as much
    faster memory access speed. Typical memory access speed on these
    boards is about 4MB/second. These boards generally have no problems
    keeping up with full ethernet speed. The only problem I've seen
    with these boards is related to the (slow) performance of 386BSD's
    malloc code when additional mbufs must be added to the pool. This
    can sometimes increase the total time to remove a packet enough
    for a ring-buffer overflow to occur.


6.4.6    Is there any PC software that will allow me to use my enormous PC
    with all of the unsupported hardware as a PC-NFS server?

    Yes.  It is called SOSS, and is available from MANY FTP sources.
    You will need the aforementioned Clarkson Packet Drivers for it
    to work, but that should cause too many problems for most people.


6.5    How can I use mtools with the 'new' floppy naming convention?

    With the adoption of BSD 4.4, there is a new way of accessing
    the floppy disk drive types.  The method uses the minor device
    number to specify different media sizes and densities.  These
    densities are established by a table from the file
    /usr/src/sys/arch/i386/isa/fd.c (in NetBSD, your mileage may
    vary).  The table in FreeBSD's fd.c is likely to be slightly
    different.

    The order of the entries defines the order of the minor
    numbers, so the table below has the following characteristics:

         /dev/fd0a    1    /* 1.44MB diskette */
        /dev/fd0b    2    /* 1.2 MB AT-diskettes */
        /dev/fd0c    3    /* 360kB in 1.2MB drive */
        /dev/fd0d    4    /* 360kB PC diskettes */
        /dev/fd0e    5    /* 3.5" 720kB diskette */
        /dev/fd0f    6    /* 720kB in 1.2MB drive */
        /dev/fd0g    7    /* 360kB in 720kB drive */

    struct fd_type fd_types[] = {
            { 18,2,0xff,0xcf,0x1b,0x6c,80,2880,1,FDC_500KBPS,2,"1.44MB"  },
            { 15,2,0xff,0xdf,0x1b,0x54,80,2400,1,FDC_500KBPS,2,"1.2MB"   },
            {  9,2,0xff,0xdf,0x23,0x50,40, 720,2,FDC_300KBPS,2,"360KB/AT"},
            {  9,2,0xff,0xdf,0x2a,0x50,40, 720,1,FDC_250KBPS,2,"360KB/PC"},
            {  9,2,0xff,0xdf,0x2a,0x50,80,1440,1,FDC_250KBPS,2,"720KB"   },
            {  9,2,0xff,0xdf,0x23,0x50,80,1440,1,FDC_300KBPS,2,"720KB/x" },
            {  9,2,0xff,0xdf,0x2a,0x50,40, 720,2,FDC_250KBPS,2,"360KB/x" },
    };

    In order to add a new device (such as a 2.44 Meg floppy) new
    tables entries are theoretically all that would be needed.  As
    new entries are created, the minor device numbers would
    increase and the associated device names would be added.
--
TSgt Dave Burgess           | Dave Burgess
NCOIC, USSTRATCOM/J6844     | *BSD FAQ Maintainer
Offutt AFB, NE              | [e-mail] or [e-mail]...