Il CD di internet/CD.iso/HOWTO/SCSI-HOW

Text File | 1995-04-20 | 81.9 KB | 2,374 lines

Copyright 1994, Drew Eckhardt <[e-mail]>

Commercial redistribution is allowed and encouraged, provided that the
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will result in the author refusing to answer questions which are answered
in newer versions, and publically denouncing your distribution as a grave
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latter is the case, a pointer to the verbatim copy must be stated at a
clearly visible place.

In short, we wish to promote dissemination of this information through as
many channels as possible. However, we do wish to retain copyright on the
HOWTO documents, to be notified of any plans to redistribute the HOWTOs
to insure that outdated versions don't spread too far, and for ALL
the information provided in the HOWTOS to be disseminated. If you have
questions, please contact Matt Welsh, the Linux HOWTO coordinator,
at [e-mail], or [phone].

IMPORTANT :

BUG REPORTS WHICH FAIL TO FOLLOW THE PROCEDURE OUTLINED IN SECTION 2 WILL
BE IGNORED.

This HOWTO covers the Linux SCSI subsystem, as implemented in Linux
kernel revision 1.1.38 and newer alpha code.  Earlier revisions of the
SCSI code are _unsupported_, and may differ significantly in terms of the
drivers implemented, performance, and options available.

For additional information, you may wish to join the SCSI channel of the
Linux activists list - mail to [e-mail]
with the line

X-MN-Admin: join SCSI

in the header.

I'm aware that this document isn't the most user-friendly,
and that there may be inaccuracies and oversights.  If
you have constructive comments on how to rectify the situation
you're free to mail me about it.

Table of contents
Section 1             Common Problems
    Section 1.1            General Flakiness
    Section 1.2         The kernel command line
    Section 1.3           A SCSI device shows up at all possible IDs
    Section 1.4         A SCSI device shows up at all possible LUNs
    Section 1.5            You get sense errors when you know the devices are error free
    Section 1.6            A kernel configured with networking does not work.
    Section 1.7              Device detected, but unable to access.
    Section 1.8            Sometimes the scsi subsystem locks up completely.
    Section 1.9         Configuring and building the kernel

Section 2            Reporting Bugs

Section 3            Hosts
    Section 3.1            Supported and Unsupported Hardware
    Section 3.2            Common Problems
    Section 3.3            Adaptec 152x, 151x, Sound Blaster 16 SCSI,
                    SCSI Pro, Gigabyte, and other AIC
                    6260/6360 based products (Standard)
    Section 3.4            Adaptec 154x, AMI FastDisk VLB,
                    Buslogic, DTC 329x (Standard)
    Section 3.5            Adaptec 174x (Standard)
    Section 3.6            Adaptec 274x (pre-ALPHA)
    Section 3.7            Allways IN2000 (ALPHA)
    Section 3.8            DPT (ALPHA)
    Section 3.9            Future Domain 16x0 with TMC-1800, TMC-18C30,
                    or TMC-18C50 chip (Standard)
    Section 3.10        Generic NCR5380 / T130B (Standard)
    Section 3.11        NCR53c810 (Standard)
    Section 3.12        Seagate ST0x/Future Domain TMC-8xx/TMC-9xx
                    (Standard)
    Section 3.13         PAS16 (Standard)
    Section 3.14        Trantor T128/T128F/T228 (Standard)
    Section 3.15        Ultrastor 14f, 24f,  34f (Standard)
    Section 3.16        Western Digital 7000 (Standard)

Section 4            Disks
    Section 4.1         Supported and Unsupported Hardware
    Section 4.2         Common Problems
    Section 4.3            Device Files
    Section 4.4            Partitioning
    Section 4.5            Disk Geometry

Section 5             CD ROMs
    Section 5.1            Supported and Unsupported Hardware
    Section 5.2            Common Problems
    Section 5.3            Device Files

Section 6            Tapes
    Section 6.1            Supported and Unsupported Hardware
    Section 6.2            Common Problems
    Section 6.3            Device Files

Section 7            Generic
    Section 7.1            Supported and Unsupported Hardware
    Section 7.2            Common Problems
    Section 7.3            Device Files

Section 8            Buyers Guide


Section 1 : Common Problems

This section lists some of the common problems that people
have.  If there is not anything here that answers your questions, you
should also consult the sections for your host adapter and the devices
in that are giving you problems.

Section 1.1 : General Flakiness
    If you experience random errors, the most likely causes are
    cabling and termination problems.

    Some products, such as those built arround the newer NCR
    chips, feature digital filtering, active signal negation,
    and aren't very sensitive to cabling problems.

    Others, such as the Adaptec 154xC, 154xCF, and 274x, are _extremely_
    sensitive and may fail with cables that work with other systems.

    I reiterate : some host adapters are _extremely_ sensitive to
    cabling and termination problems and therefore, cabling and
    termination should be the first things checked when there are
    problems.

    To minimize your problems, you should use cables which

        1.  Claim SCSI-II compliance
    2.  Have a characteristic impedance of 132 ohms
    3.  All come from the same source to avoid impedance mismatches
    4.  Come from a reputable vendor such as Amphenol who

    Termination power should be provided by _all_ devices on
    the SCSI bus, through a diode to prevent current backflow,
    so that sufficient power is available at the ends of the cable
    where it is needed.  To prevent damage if the bus is shorted,
    TERMPWR should be driven through a fuse or other current
    limiting device.

    If multiple devices, external cables, or FAST SCSI 2 are used,
    active or forced perfect termination should be used on both ends
    of the SCSI bus.

    See the Comp.Periphs.Scsi FAQ (available on tsx-11 in
    pub/linux/ALPHA/scsi) for more information about active
    termination.

Section 1.2 : The kernel command line

    Other parts of the documentation refer to a "kernel command line".

    The kernel command line is a set of options you may specify
    from either the LILO : prompt after an immage name, or in the
    append field in your LILO configuration file (typically
    /etc/lilo/config).

    Boot your system with LILO, and hit one of the alt, control, or
    shift keys when it first comes up to get a prompt.  LILO
    should respond with

        :

    At this prompt, you can select a kernel image to boot, or list
    them with ?.  Ie

        :?

        ramdisk floppy harddisk

    To boot that kernel with the command line options you have
    selected, simply enter the name followed by a white space delimited
    list of options, terminating with a return.

    Options take the form of

        variable=valuelist

    Where valuelist may be a single value or comma delimited list
    of values with no whitespace.  With the exception of root device,
    individual values are numbers, and may be specified in either
    decimal or hexadecimal.

    Ie, to boot linux with an Adaptec 1520 clone not recognized
    at bootup, you might type


    Ie, to boot linux with an Adaptec 1520 clone not recognized
    at bootup, you might type

        :floppy aha152x=0x340,11,7,1

    If you don't care to type all of this at boot time, it is also
    possible to use the LILO configuration file "append" option
    with LILO .13 and newer.


Section 1.3 :  A SCSI device shows up at all possible IDs

    If this is the case, you have strapped the device at the same
    address as the controller (typically, 7, although some boards
    use other addresses).  Please change the jumper settings.

Section 1.4 :  A SCSI device shows up at all possible LUNs

    The device has buggy firmware.  There is a list of buggy devices
    in the kernel sources in drivers/scsi/scsi.c in the variable
    blacklist.  Try adding the device to the list and see if this helps.

Section 1.5 :  You get sense errors when you know the devices are error free

    Sometimes this is caused by bad cables or impropper termination.

    Your SCSI bus must be terminated at both ends (using external
    terminators, or onboard terminators on the host adapter or
    devices) and not in the middle.

    The SCSI-2 specification recommends active termination at both ends
    of the cable.  For SCSI configurations with just one device and a
    short cable, you can probably get away with passive termination,
    but if you start having SCSI reliability problems when you start
    adding more devices or using a longer cable then you should try
    active termination.  See the Comp.Periphs.Scsi FAQ (available on
    tsx-11 in pub/linux/ALPHA/scsi) for more information about active
    termination.

Section 1.6 :  A kernel configured with networking does not work.

    The auto-probe routines for many of the network drivers
    are not passive, and will interfere with operation with some
    of the SCSI drivers.

Section 1.7 :  Device detected, but unable to access.

    A SCSI device is detected by the kernel, but you are unable to
    access it - ie mkfs /dev/sdc, tar xvf /dev/rst2, etc fails.

    You don't have a special file in /dev for the device.

    Unix devices are identified as either block or character (block
    devices go through the buffer cache, character devices do not) devices,
    a major number (ie which driver is used - block major 8 corresponds
    to SCSI disks) and a minor number (ie which unit is being accessed
    through a given driver - ie character major 4, minor 0 is the first
    virtual console, minor 1 the next, etc).  However, accessing devices
    through this separate namespace would break the unix/Linux metaphor of
    "everything is a file," so character and block device special files
    are created under /dev.  This lets you access the raw third SCSI disk
    device as /dev/sdc, the first serial port as /dev/ttyS0, etc.

    The preferred method for creating a file is using the MAKDEV script -
    cd /dev

    and run MAKEDEV (as root) for the devices you want to create - ie

    ./MAKEDEV sdc

    wildcards "should" work - ie

    ./MAKEDEV sd\*

    "should" create entries for all SCSI disk devices (doing this should
    create /dev/sda through /dev/sdp, with fifteen partition entries for
    each)

    ./MAKEDEV sdc\*

    "should" create entries for /dev/sdc and all fifteen permissible
    partitions on /dev/sdc, etc.

    I say "should" because this is the standard unix behavior - the MAKEDEV
    script in your installation may not conform to this behavior, or may
    have restricted the number of devices it will create.

    If MAKEDEV won't do the right magic for you, you'll have to create the
    device entries by hand with the mknod command.

    The block/character type, major, and minor numbers are specified for the
    various SCSI devices in Subsection 3 : Device Files in the appropriate
    section.

    Take those numbers, and use (as root)

    mknod /dev/device b|c major minor

    ie -

    mknod /dev/sdc b 8 32
    mknod /dev/rst0 c 9 0

Section 1.8 :   SCSI System Lockups

    This could be one of a number of things.  Also see the section for
    your specific host adapter for possible further solutions.

    There are cases where the lockups seem to occur when multiple devices
    are in use at the same time.  In this case, you can try contacting
    the manufacturer of the devices and see if firmware upgrades are
    available which would correct the problem.  If possible, try a
    different scsi cable, or try on another system.  This can also
    be caused by bad blocks on disks, or by bad handling of DMA by the
    motherboard (for host adapters that do DMA).  There are probably
    many other possible conditions that could lead to this type of event.

    Sometimes these problems occur when there are multiple devices in
    use on the bus at the same time.  In this case, if your host
    adapter driver supports more than one outstanding command on the bus
    at one time, try reducing this to 1 and see if this helps. If you
    have tape drives or slow cdrom drives on the bus, this might not be
    a practical solution.

Section 1.9 : Configuring and building the kernel

    Unused SCSI drivers eat up valuable memory, aggravating
    memory shortage problems on small systems because kernel
    memory is unpagable.

    So, you will want to build a kernel tuned for your
    system, with only the drivers you need installed.

    cd to /usr/src/linux

    If you are using a root device other than the current
    one, or something other than 80x25 VGA, and you are
    writing a boot floppy, you should edit the makefile,
    and make sure the

        ROOT_DEV =

    and

        SVGA_MODE =

    lines are the way you want them.

    If you've installed any patches, you may wish to guarantee that all
    files are rebuilt.  If this is the case, you should type

        make mrproper

    Irregardless of weather you ran make mrproper, type

        make config

    and answer the configuration questions.  Then run

        make depend

    and finally

        make

    Once the build completes, you may wish to update the
    lilo configuration, or write a boot floppy.  A boot floppy
    may be made by running

        make zdisk

Section 2 : Reporting Bugs

The Linux SCSI developers don't necessarily maintain old revisions
of the code due to space constraints.  So, if you are not running the
latest publically released Linux kernel (note that many of the Linux
distributions, such as MCC, SLS, Yggdrasil, etc. often lag one or more
revisions behind this) chances are we will be unable to solve your
problem.  So, before reporting a bug, please check to see if it exists
with the latest publically available kernel.

If after upgrading, and reading this document thoroughly, you still
believe that you have a bug, please mail a bug report to the SCSI channel
of the mailing list where it will be seen by many of the people who've
contributed to the Linux SCSI drivers.

In your bug report, please provide as much information as possible
regarding your hardware configuration, and the exact text of
all of the messages that Linux prints when it boots and when the
error condition occurs.  Failure to provide the exact text of any and
all messages may result in misdiagnosis of your problem.

The bottom line is that if we can't reproduce your bug, and you can't
point at us what's broken, it won't get fixed.

Assuming you don't yet have Linux up and running, a good way to provide
the information we need would be to perform the following procedure :

Format a floppy diskette under DOS.  Note that if you have a distribution
which mounts the root diskette off of floppy rather than RAM drive, you'll
have to format a diskette readable in the drive not being used to mount
root.

Boot Linux, and login as root

    mkdir /tmp/dos

Insert the diskette in a drive not being used to mount root, and
mount it.  Ie

    mount -t msdos /dev/fd0 /tmp/dos

    or

    mount -t msdos /dev/fd1 /tmp/dos

Insure that the /proc filesystem is mounted.

    grep proc /etc/mtab

If the /proc filesystem is not mounted, mount it

    mkdir /proc
    chmod 755 /proc
    mount -t proc /proc /proc

Copy the kernel revision and messages into a log file

    cat /proc/version > /tmp/dos/log
    cat /proc/kmsg >> /tmp/dos/log

Type CNTRL-C after a second or two.

Unmount the DOS floppy

    umount /tmp/dos

And shutdown Linux

    shutdown

Reboot into DOS, and using your favorite communications software include
the log file in your trouble mail.

Section 3 : Hosts

This section gives specific information about the various host adapters that
are supported in some way or another under linux.

Section 3.1 : Supported and Unsupported Hardware
Drivers in the distribution kernel :

Adaptec 152x, Adaptec 154x (including clones from Bustek and DTC 329x
boards), Adaptec 174x, Future Domain 850, 885, 950, and other boards
in that series (but not the 880 board unless you make the appropriate
patch), Future Domain 16x0 with TMC-1800 or TMC-18C50 chip, PAS16
SCSI ports, Seagate ST0x, Trantor T128 boards, Ultrastor 14F, 24F, and 34F,
and Western Digital 7000.

Alpha drivers :
Adaptec 2742
DPT
Richoh GSI-8

Many of the ALPHA drivers are available via anonymous FTP from
tsx-11.mit.edu:/pub/linux/ALPHA/scsi

Drivers that are being developed, but aren't publically available yet,
and modifications needed to make existing drivers compatable with
other boards :

Announcements WILL be made when drivers are available for public
alpha testing.  Until then, please don't use up the developers'
valuable time with mail asking for release dates, etc.

Adaptec 2842, 2940, various AIC 7770/7870 implementations

    An Adaptec 2742 driver for the EISA AIC-7770 board has
    been developed, and with some modifications (perhaps
    limited to detection) should support these boards.

NCR53c8x0/7x0

    A NCR53c810 drviver has been developed, and with modifications
    ranging from minor to severe should support these chips

    NCR53c815 - detection changes

    NCR53c820, NCR53c825 - detection changes, possible initialization
    changes, ultimately support for WDTR messages.

    NCR53c720 - detection changes, initializaion changes, modification
    of the assembler to use the 720's register mapping

    NCR53c710 - detection changes, initialization changes, modification
    of assembler, modification of the NCR code to use fatal
    interrupts or GPIO generated non fatal interrupts for
    command completion, elimination of add with carry
    instructions through DSA alignment modification.

    NCR53c700, NCR53c700-66 - detection changes, initialization changes,
    modification of NCR code to not use DSA, modification of Linux
    code to handle context switches.

NCR53c9x family

Qlogic

Trantor T130B / generic NCR53c400 using pseudo DMA

    The Trantor T130B uses an NCR53c400 chip, essentially a more
    integrated, low-performance ISA SCSI solution adding a pair of
    128 byte buffers and on-chip "pseudo-DMA" hardware to
    a NCR5380 ASIC core

    Kevin's patches to support the on-chip buffers and interrupts
    on the board work, and an effort to integrate them into an
    ALPHA kernel is being made.

SCSI hosts that will not work :

All parallel->SCSI adapters, Rancho SCSI boards, and Grass Roots SCSI
boards.

SCSI hosts that will NEVER work :

Non Adaptec compatable DTC boards (including the 3270 and 3280).

Aquiring programming information requires a non-disclosure agreement
with DTC.  This means that it would be impossible to distribute a
Linux driver if one were written, since complying with the NDA would
mean distributing no source, in violation of the GPL, and complying
with the GPL would mean distributing source, in violation of the NDA.

If you want to run Linux on an unsupported piece of hardware, your
options are to either write a driver yourself (Eric Youngdale and I are
usually willing to answer technical questions concerning the Linux
SCSI drivers) or to commision a driver.

Section 3.2 : Common Problems
Section 3.2.1 : SCSI timeouts
    Make sure interrupts are enabled correctly, and there are no
    IRQ, DMA, or address conflicts with other boards.

Section 3.2.2 : Failure of autoprobe routines on boards that rely on
    BIOS for autoprobe.

    If your SCSI adapter is one of the following :

        Adaptec 152x, Adaptec 151x, Adaptec AIC-6260,
        Adaptec AIC-6360, Future Domain 1680, Future Domain TMC-950,
        Future Domain TMC-8xx, Trantor T128, Trantor T128F,
        Trantor T228F, Seagate ST01, Seagate ST02, or a
        Western Digital 7000

    and it is not detected on bootup, ie you get a

        scsi : 0 hosts

    message or a

        scsi%d : type

    message is not printed for each supported SCSI adapter installed
    in the system, you may have a problem with the autoprobe routine
    not knowing about your board.

    Autodetection will fail for drivers using the BIOS for autodetection
    if the BIOS is disabled.  Double check that your BIOS is enabled,
    and not conflicting with any other peripherial BIOSes.

    Autodetection will also fail if the board's "signature" and/or
    BIOS address don't match known ones.

    If the BIOS is installed, please use DOS and DEBUG to
    find a signature that will detect your board -

    Ie, if your board lives at 0xc8000, under DOS do

    debug
    d c800:0
    q

    and send a message to the SCSI channel of the mailing list with
    the ASCII message, with the length and offset from the base
    address (ie, 0xc8000).  Note that the EXACT text is required,
    and you should provide both the hex and ASCII portions of
    the text.

    If no BIOS is installed, and you are using an Adaptec 152x,
    Trantor T128, or Seagate driver, you can use command line
    or compile time overrides to force detection.

    Please consult the appropriate subsection for your SCSI board
    as well as Section 1.1 :


Section 3.2.3 : Failure of boards using memory mapped I/O

    (This include the Trantor T128 and Seagate boards, but not the
    Adaptec, Generic NCR5380, PAS16, and Ultrastor drivers)

    This is often caused when the memory mapped I/O ports
    are incorrectly cached.  You should have the board's
    address space marked as uncachable in the XCMOS settings.

    If this is not possible, you will have to disable cache
    entirely.

Section 3.2.4 : Failure of bootable kernels for a ALPHA drivers

        This You get resulting in a "kernel panic : cannot mount root device"
    message, or it does not work with your Linux distribution.

    You'll need to edit the binary image of the kernel (before
    or after writing it out to disk), and modify a few two byte
    fields (little endian) to gurantee that it will work on your
    system.

    1.  default swap device at offset 502, this should be set to 0

    2.  ram disk size at offset 504, this should be set to the size
        of the boot floppy in K - ie, 5.25" = 1200, 3.5" = 1440.

        This means the bytes are

        3.5" : 0xA0 0x05
        5.25" : 0xB0  0x04

    3.  root device offset at 508, this should be 0, ie the boot
        device.

    dd or rawrite the file to a disk.  Insert the disk in the
    first floppy drive, wait until it prompts you to insert
    the root disk, and insert the root floppy from your
    distribution.


Section 3.2.5 : Installing a device driver not included with the distribution
    kernel

    You need to start with the version of the kernel used by the
    driver author.  This revision may be alluded to in the documentation
    included with the driver.

    Various recent kernel revisions can be found at
        nic.funet.fi:/pub/OS/Linux/PEOPLE/Linus

    as linux-version.tar.gz

    They are also mirrored at tsx-11.mit.edu and various other sites.

    cd to /usr/src.

    Remove your old Linux sources, if you want to keep a backup copy
    of them

    mv linux linux-old

    Untar the archive

    gunzip < linux-0.99.12.tar.gz | tar xvfp -

    Apply the patches.  The patches will be relative to some directory
    in the filesystem.  By examining the output file lines in the patch
    file (grep for ^---), you can tell where this is - ie patches with
    these lines

    --- ./kernel/blk_drv/scsi/Makefile

    --- ./config.in Wed Sep  1 16:19:33 1993


    would have the files relative to /usr/src/linux.

    Untar the driver sources at an appropriate place - you
    can type

    tar tfv patches.tar

    to get a listing, and move files as necessary (The SCSI driver files
    should live in /usr/src/linux/kernel/drivers/scsi)

    Either cd to the directory they are relative to and type

    patch -p0 < patch_file

    or tell patch to strip off leading path components.  Ie,
    if the files started with

    --- linux-new/kernel/blk_drv/scsi/Makefile

    and you wanted to apply them while in /usr/src/linux, you
    could cd to /usr/src/linux and type

    patch -p1 <  patches

    to strip off the "linux-new" component.

    After you have applied the patches, look for any patch rejects,
    which will be the name of the rejected file with a # suffix appended.

    find /usr/src/linux/ -name "*#" -print

    If any of these exist, look at them.  In some cases, the
    differences will be in RCS identifiers and will be harmless,
    in other cases, you'll have to manually apply important
    parts.  Documentation on diffs files and patch is beyond the
    scope of this document.

    See also Section 1.8 : Configuring and building the kernel

3.2.6 :  Installing a driver that has no patches

    In some cases, a driver author may not offer patches with
    the .c and .h files which comprise his driver, or the patches
    may be against an older revision of the kernel and not go
    in cleanly.

    1.  Copy the .c and .h files into /usr/src/linux/drivers/scsi

    2.  Add the configuration option

        Edit /usr/src/linux/config.in, and add a line in the

            *
            * SCSI low-level drivers
            *

        section, add a boolean configuration variable for your
        driver.  Ie,

        bool 'Allways IN2000 SCSI support' CONFIG_SCSI_IN2000 y

    3.  Add the makefile entries

        Edit /usr/src/linux/drivers/scsi/Makefile, and add
        an entry like

        ifdef CONFIG_SCSI_IN2000
        SCSI_OBS := $(SCSI_OBJS) in2000.o
        SCSI_SRCS := $(SCSI_SRCS) in2000.c
        endif

        before the

        scsi.a: $(SCSI_OBJS)

        line in the makefile, where the .c file is the .c
        file you copied in, and the .o file is the basename
        of the .c file with a .o suffixed.

    4.  Add the entry points

        Edit /usr/src/linux/drivers/scsi/hosts.c, and
        add a #inlclude for the header file, conditional
        on the CONFIG_SCSI preprocessor define you
        added to the configuration file.  Ie, after

        #ifdef CONFIG_SCSI_GENERIC_NCR5380
        #include "g_NCR5380.h"
        #endif

        you might add

        #ifdef CONFIG_SCSI_IN2000
        #include "in2000.h"
        #endif

        You will also need to add the Scsi_Host_Template
        entry into the scsi_hosts[] array.  Take a look
        into the .h file, and you should find a #define that
        looks something like this :

        #define IN2000 {"Always IN2000", in2000_detect, \
                in2000_info, in2000_command,    \
                in2000_queuecommand,            \
                in2000_abort,                   \
                in2000_reset,                   \
                NULL,                           \
                in2000_biosparam,               \
                1, 7, IN2000_SG, 1, 0, 0}

        the name of the preprocessor define, and add
        it into the scsi_hosts[] array, conditional on
        definition of the preprocessor symbol you used
        in the configuration file.

        Ie, after

        #ifdef CONFIG_SCSI_GENERIC_NCR5380
                GENERIC_NCR5380,
        #endif

        you might add

        #ifdef CONFIG_SCSI_IN2000
            IN2000,
        #endif

    See also Section 1.8 : Configuring and building the kernel

Section 3.3 : Adaptec 152x, 151x, Sound Blaster 16 SCSI, SCSI Pro,
    Gigabyte, and other AIC 6260/6360 based products (Standard)
Supported Configurations :
BIOS addresses : 0xd8000, 0xdc000, 0xd0000, 0xd4000, 0xc8000, 0xcc000, 0xe0000,
    0xe4000.
Ports : 0x140, 0x340
IRQs : 9, 10, 11, 12
DMA is not used
IO : port mapped

Autoprobe :

    Works with many boards with an installed BIOS.  All
    other boards, including the Adaptec 1510, and Sound Blaster16 SCSI
    must use a kernel command line or compile time override.

Autoprobe Override :
Compile time :
Define PORTBASE, IRQ, SCSI_ID, RECONNECT as appropriate, see Defines

kernel command line : aha152x=<PORTBASE>,<IRQ>,<SCSI-ID>,<RECONNECT>

Usually, SCSI-ID will be 7 and RECONNECT non-zero.

To force detection at 0x340, IRQ 11, at SCSI-ID 7, allowing
disconnect/reconnect, you would use the following command line
option :

aha152x=0x340,11,7,1

Antiquity Problems, fix by upgrading :
1.  The driver fails with VLB boards.  There was a timing problem
    in kernels older than revision 1.0.5.

Defines :
AUTOCONF      : use configuration the controller reports (only 152x)
IRQ           : override interrupt channel (9,10,11 or 12) (default 11)
SCSI_ID       : override scsiid of AIC-6260 (0-7) (default 7)
RECONNECT     : override target dis-/reconnection/multiple
    outstanding command - set to non-zero to enable, zero to
    disable.
DONT_SNARF     : Don't register ports (pl12 and below)
SKIP_BIOSTEST  : Don't test for BIOS signature (AHA-1510 or disabled BIOS)
PORTBASE       : Force port base. Don't try to probe

Section 3.4 : Adaptec 154x, AMI FastDisk VLB, Buslogic, DTC 329x (Standard)
Supported Configurations :
Ports : 0x330 and 0x334
IRQs : 9, 10, 11, 12, 14, 15
DMA channels : 5, 6, 7
IO : port mapped, bus master

Autoprobe : works with all supported configurations, does not
    require an installed BIOS.

Autoprobe override : none

Note: Buslogic makes a series of boards that are software compatible with
the Adaptec 1542, and these come in ISA, VLB and EISA flavors.

Antiquity Problems, fix by upgrading :

1.  Linux kernel revisions prior to .99.10 don't support the 'C'
    revision.

2.  Linux kernel revisions prior to .99.14k don't support the 'C'
    revision options for

    - BIOS support for the extended mapping for disks > 1G

    - BIOS support for > 2 drives

    - BIOS support for autoscanning the SCSI bus

3.  Linux kernel revisions prior to .99.15e don't support the 'C'
    with the BIOS support for > 2 drives turned on and the
    BIOS support for the extended mapping for disks > 1G turned off.

4.  Linux kernel revisions prior to .99.14u don't support the 'CF'
    revisions of the board.

5.  Linux kernel revisions prior to 1.0.5 have a race condition
    when multiple devices are accessed at the same time.

Common problems :

1.  There are unexpected errors with a 154xC or 154xCF board,

    Early examples of the 154xC boards have a high slew rate on
    one of the SCSI signals, which results in signal reflections
    when cables with the wrong impedance are used.

    Newer boards aren't much better, and also suffer from extreme
    cabling and termination sensitivity.

    See also Common Problems #2 and #3 and Section 1 : Common Problems,
    Subsection 1.1 : General Flakiness

2.  There are unexpected errors with a 154xC or 154x with
    both internal and external devices connected.

    This is probably a termination problem.  In order to
    use the software option to disable host adapter termination,
    you must turn switch 1 off.

    See also Common Problems #1 and #3 and Section 1 : Common Problems,
    Subsection 1.1 : General Flakiness

3.  The SCSI subsystem locks up completely.

    There are cases where the lockups seem to occur when multiple devices
    are in use at the same time.  In this case, you can try contacting
    the manufacturer of the devices and see if firmware upgrades are
    available which would correct the problem.  As a last resort, you
    can go into aha1542.h and change AHA1542_MAILBOX to 1.  This will
    effectively limit you to one outstanding command on the scsi bus at
    one time, and may help the situation.  If you have tape drives or
    slow cdrom drives on the bus, this might not be a practical solution.

    See also Common Problems #1 and #2 and
    Section 1.1 : Common Problems : General Flakiness
    Section 1.8 : Common Problems : SCSI Lockups


4.  An "Interrupt received, but no mail" message is printed on bootup
    and your SCSI devices are not detected.

    Disable the BIOS options to support the extended mapping for
    disks > 1G, support for > 2 drives, and for autoscanning the
    bus.  Or, upgrade to Linux .99.14k or newer.

Section 3.5 : Adaptec 174x
Supported Configurations :
Slots : 1-8
Ports : EISA board, not applicable
IRQs : 9, 10, 11, 12, 14, 15
DMA Channels : EISA board, not applicable
IO : port mapped, bus master

Autoprobe : works with all supported configurations

Autoprobe override : none

Note: This board has been discontinued by Adaptec.

Common Problems :
1. If the Adaptec 1740 driver prints the message
    "aha1740: Board detected, but EBCNTRL = %x, so disabled it."

    your board was disabled because it was not running in enhanced
        mode.  Boards running in standard 1542 mode are not supported.

Section 3.6 : Adaptec 274x (Pre-ALPHA)
    available via anonymous FTP from ftp.cpsc.ucalgary.ca
    /pub/systems/linux/aha274x.
Supported Configurations :
Slots : 1-12
Ports : EISA board, not applicable
IRQs : ALL
DMA Channels : EISA board, not applicable
IO : port mapped, bus master

BIOS MUST be enabled

Section 3.7 : Allways IN2000  (ALPHA)
ALPHA available via ftp tsx-11.mit.edu/pub/linux/ALPHA/SCSI/in2000
    driver is in2000.tar.z, bootable kernel zImage
Ports : 0x100, 0x110, 0x200, 0x220
IRQs : 10, 11, 14, 15
DMA is not used
IO : port mapped

Autoprobe : BIOS not required

Autoprobe override : none

Common Problems :

1.  There are known problems in systems with IDE drives and with
    swapping.

Section 3.8 : DPT
ALPHA available via ftp ftp.ibp.fr in directory /pub/linux/ALPHA/scsi

Section 3.9 : Future Domain 16x0 with TMC-1800, TMC-18C30, TMC-18C50,
    or TMC-36C70 chip
Supported Configurations :
BIOSs :  2.0, 3.0, 3.2, 3.4
BIOS Addresses :    0xc8000, 0xca000, 0xce000, 0xde000
Ports : 0x140, 0x150, 0x160, 0x170
IRQs : 3, 5, 10, 11, 12, 14, 15
DMA is not used
IO : port mapped

Autoprobe : works with all supported configurations, requires
    installed BIOS

Autoprobe Override : none

Antiquity Problems, fix by upgrading :

1.  Old versions do not support the TMC-18C50 chip, and will fail with
    newer boards.

2.  Old versions will not have the most current BIOS signatures for
    autodetection.

3.  Versions prior to the one included in Linux 1.0.9 and 1.1.6
    don't support the new SCSI chip or 3.4 BIOS.

Section 3.10 : Generic NCR5380 / T130B
Supported and Unsupported Configurations :
Ports : all
IRQs : all
DMA channels - DMA is not used
IO : port mapped

Autoprobe : none

Autoprobe Override :
Compile time : Define GENERIC_NCR5380_OVERRIDE to be an array of tupples
with port, irq, dma, board type - ie
#define GENERIC_NCR5380_OVERRIDE {{0x330, 5, DMA_NONE, BOARD_NCR5380}}

for a NCR5380 board at port 330, IRQ 5.

#define GENERIC_NCR5380_OVERRIDE {{0x350, 5, DMA_NONE, BOARD_NCR53C400}}

for a T130B at port 0x350.

Older versions of the code eliminate the BOARD_* entry.

The symbolic IRQs IRQ_NONE and IRQ_AUTO may be used.

kernel command line : ncr5380=port,irq
              ncr5380=port,irq,dma
              ncr53c400=port,irq

255 may be used for no irq, 254 for irq autoprobe.

Common Problems :

1. Using the T130B board with the old (pre public release 6) generic
    NCR5380 driver which doesn't support the ncr53c400 command
    line option.

    The NCR5380 compatable registers are offset eight from
    the base address.  So, if your address is 0x350, use

    ncr53480=0x358,254

    on the kernel command line.

Antiquity problems, fix by upgrading :
1.  The kernel locks up during disk access with T130B or other
    NCR53c400 boards

    Pre-public release 6 versions of the Generic NCR5380
    driver didn't support interrupts on these boards.
    Upgrade.


Notes : the generic driver doesn't support DMA yet, and pseudo-DMA
    isn't supported in the generic driver.

Section 3.11 : NCR53c810 (Standard)

Supported and Unsupported Configurations :
Base addresses : ALL
IRQs : ALL
DMA channels : PCI, not applicable
IO : port mapped, busmastering

Autoprobe : requires PCI BIOS, uses PCI BIOS routines to
    search for devices and read configuration space

The driver uses the pre-programmed values in some registers for
initialization, so a BIOS must be installed.

Antiquity Problems, fix by upgrading :

1.  Older versions of Linux had a problem with swapping

    See Section 4.2.7 : Disks :  System Hangs When Swapping

Common Problems :

1.  Many people have encountered problems where the chip worked
    fine under DOS, but failed under Linux with a timeout on
    test 1 due to a lost interrupt.

    This is often due to a mismatch between the IRQ hardware
    jumper for a slot or mainboard device and the value set
    in the CMOS setup.

    It may also be due to PCI INTB, INTC, or INTD being selected
    on a PCI board in a system which only supports PCI INTA.

    Finally, PCI should be using level-sensitive rather
    than edge triggered interrupts.  Check that your board
    is jumpered for level-sensitive, and if that fails
    try edge-triggered because your system may be
    broken.

    This problem is especially common with Viglen some Viglen
    motherboards, where the mainboard IRQ jumper settings are
    NOT as documented in the manual.  I've been told that what
    claims to be IRQ5 is really IRQ9, your mileage will vary.

2.  Lockups occur when using an S3928P, X11, and the NCR
    chip at the same time.

    There are hardware bugs in at least some S3928P chip.  Don't
    do this.

3.  You get a message on boot up indicating that the I/O mapping
    was disabled because base address 0 bits 0..1 indicated a
    non I/O mapping

    This is due to a BIOS bug in some machines which results in
    dword reads of configuration regsisters returning the
    high and low 16 bit words swapped.

4.  Some systems have problems if PCI write posting, or CPU->
    PCI buffering are enabled.  If you have problems,
    disable these options.

5.  Some systems with the NCR SDMS software in an onboard BIOS
        ROM and in the system BIOS are unable to boot DOS.
    Disabling the image in one place should rectify this
    problem.

6.  Some systems have hideous, broken, BIOS chips.  Don't
    make any bug reports until you've made sure you have
    the newest ROM from your vendor.

    - Intel P90 boards require revision 1.00.04.AX1

Section 3.12 : Seagate ST0x/Future Domain TMC-8xx/TMC-9xx
Supported and Unsupported Configurations :
Base addresses : 0xc8000, 0xca000, 0xcc000, 0xce000, 0xdc000, 0xde000
IRQs : 3, 5
DMA channels : DMA is not used
IO : memory mapped

Autoprobe : probes for address only, IRQ is assumed to be 5,
    requires installed BIOS.

Autoprobe Override :
Compile time : Define OVERRIDE to be the base address, CONTROLLER to
FD or SEAGATE as appropriate, and IRQ to the IRQ.

kernel command line : st0x=address,irq or tmc8xx=address,irq (only works
    for .99.13b and newer)

Antiquity Problems, fix by upgrading :

1.  Versions prior to the one in the Linux .99.12 kernel had a problem
    handshaking with some slow devices, where

    This is what happens when you write data out to the bus

    1.  Write byte to data register, data register is asserted to bus
    2.  time_remaining = 12us
    3.  wait while time_remaining > 0 and REQ is not asserted
    4.  if time_remaining > 0, assert ACK
    5.  wait while time remaining > 0  and REQ is asserted
    6.  deassert ACK

    The problem was encountered in slow devices that do the command
    processing as they read the command, where the REQ/ACK handshake
    takes over 12us - REQ didn't go false when the driver expected it
    to, so the driver ended up sending multiple bytes of data for
    each REQ pulse.

2.  With Linux .99.12, a bug was introduced when I fixed the arbitration
    code, resulting in failed selections on some systems.  This was
    fixed in .99.13.
A
Common Problems :

1.  There are command timeouts when Linux attempts to read the partition
    table or do other disk access.

    The board ships with the defaults set up for MSDOS, ie interrupts
    are disabled.  To jumper the board for interrupts, on the Seagate
    use jumper W3 (ST01) or JP3 (ST02) and short pins F-G to select
    IRQ 5.

2.  The driver can't handle some devices, particularly cheap SCSI
    tapes and CDROMs.

    The Seagate ties the SCSI bus REQ/ACK handshaking into the PC bus
    IO CHANNEL READY and (optionally) 0WS signals.  Unfortunately, it
    doesn't tell you when the watchdog timer runs out, and you have
    no way of knowing for certain that REQ went low, and may end up
    seeing one REQ pulse as multiple REQ pulses.

    Dealing with this means using a tight loop to look for REQ to
    go low, with a timeout incase you don't catch the transition due
    to an interrupt, etc.  This results in a performance decrease, so it
    would be undesireable to apply this to all SCSI devices.  Instead,
    it is selected on a per-device basis with the "borken" field for
    the given SCSI device in the scsi_devices array.  If you run into
    problems, you should try adding your device to the list of
    devices for which borken is not reset to zero (currently,
    only the TENEX CDROM drives).

3.  A future domain board (specific examples include the 840,841,
    880, and 881) doesn't work.

    A few of the Future domain boards use the Seagate
    register mapping, and have the MSG and CD bits of the
    status register flipped.

    You should edit seagate.h, swapping the definitions for
    STAT_MSG and STAT_CD, and recompile the kernel with
    CONTROLLER defined to SEAGATE and an appropriate
    IRQ and OVERRIDE specified.

4.  When attempting to fdisk your drive, you get error messages
    indicating that the HDIO_REQ or HDIO_GETGEO ioctl failed,
    or

    You must set heads sectors and cylinders.
    You can do this from the extra functions menu.


    See Section 4.4 : Disks : Partitioning

5.  After manually specifying the drive geometry, subsequent
    attempts to read the partition table result in partition
    boundary not on a cylinder boundary, physical and logical
    boundaries don't match, etc. error messages.

    See Section 4.4 : Disks : Partitioning


6.  Some systems which worked prior to .99.13 fail with newer
    versions of Linux.  Older versions of Linux assigned the
    CONTROL and DATA registers in an order different than that
    outlined in the Seagate documentation, which broke on some
    systems.  Newer versions make the assignment in the correct
    way, but this breaks other systems.

    The code in seagate.c looks like this now :

    cli();
    DATA = (unsigned char) ((1 << target) | (controller_type == SEAGATE ? 0x80 : 0x40));
    CONTROL = BASE_CMD | CMD_DRVR_ENABLE | CMD_SEL |
        (reselect ? CMD_ATTN : 0);
    sti();

    Changing this to

    cli();
    CONTROL = BASE_CMD | CMD_DRVR_ENABLE | CMD_SEL |
        (reselect ? CMD_ATTN : 0);
    DATA = (unsigned char) ((1 << target) | (controller_type == SEAGATE ? 0x80 : 0x40));
    sti()

    may fix your problem.

Defines :

FAST or FAST32 will use blind transfers where possible

ARBITRATE will cause the host adapter to arbitrate for the
    bus for better SCSI-II compatability, rather than just
        waiting for BUS FREE and then doing its thing.  Should
    let us do one command per Lun when I integrate my
    reorganization changes into the distribution sources.

SLOW_HANDSHAKE will allow compatability with broken devices that don't
    handshake fast enough (ie, some CD ROM's) for the Seagate
    code.

SLOW_RATE=x, x some number will let you specify a default
    transfer rate if handshaking isn't working correctly.

Section 3.13 : PAS16 SCSI
Supported and Unsupported Configurations :
Ports : 0x388, 0x384, 0x38x, 0x288
IRQs : 10, 12, 14, 15
    IMPORTANT : IRQ MUST be different from the IRQ used for the sound
    portion of the board.
DMA is not used for the SCSI portion of the board
IO : port mapped

Autoprobe : does not require BIOS

Autoprobe Override :
Compile time : Define PAS16_OVERRIDE to be an array of port, irq
tupples.  Ie

#define PAS16_OVERRIDE {{0x388, 10}}

for a board at port 0x388, IRQ 10.

kernel command line :
pas16=port,irq

Defines :
AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
for commands that return with a CHECK CONDITION status.

PSEUDO_DMA - enables PSEUDO-DMA hardware, should give a 3-4X performance
increase compared to polled I/O.

PARITY - enable parity checking.  Not supported

SCSI2 - enable support for SCSI-II tagged queueing.  Untested


UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
         only really want to use this if you're having a problem with
         dropped characters during high speed communications, and even
         then, you're going to be better off twiddling with transfersize.

USLEEP - enable support for devices that don't disconnect.  Untested.


Common problems :

1.  Command timeouts, aborts, etc.

    You should install the NCR5380 patches that I posted to the net
    some time ago, which should be integrated into some future alpha
    release.  These patches fix a race condition in earlier NCR5380
    driver cores, as well as fixing support for multiple devices on
    NCR5380 based boards.

    If that fails, you should disable the PSEUDO_DMA option by
    changing the #define PSEUDO_DMA line in drivers/scsi/pas16.c to #undef
    PSEUDO_DMA.

    Note that the later should be considered a last resort, because
    there will be a severe performance degradation.



Section 3.14 : Trantor T128/T128F/T228
Supported and Unsupported Configurations :
Base addresses :  0xcc000, 00xc8000, 0xdc000, 0xd8000
IRQs : none, 3, 5, 7 (all boards)
    10, 12, 14, 15 (T128F only)
DMA is not used.
IO : memory mapped

Autoprobe : works for all supported configurations, requires
    installed BIOS.

Autoprobe Override :
Compile time : Define T128_OVERRIDE to be an array of address, irq
tupples.  Ie

#define T128_OVERRIDE {{0xcc000, 5}}

for a board at address 0xcc000, IRQ 5.

The symbolic IRQs IRQ_NONE and IRQ_AUTO may be used.

kernel command line : t128=address,irq

-1 may be used for no irq, -2 for irq autoprobe.

Defines :
AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
for commands that return with a CHECK CONDITION status.

PSEUDO_DMA - enables PSEUDO-DMA hardware, should give a 3-4X performance
increase compared to polled I/O.

PARITY - enable parity checking.  Not supported

SCSI2 - enable support for SCSI-II tagged queueing.  Untested


UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
         only really want to use this if you're having a problem with
         dropped characters during high speed communications, and even
         then, you're going to be better off twiddling with transfersize.

USLEEP - enable support for devices that don't disconnect.  Untested.

Common Problems :
1.  Command timeouts, aborts, etc.

    You should install the NCR5380 patches that I posted to the net
    some time ago, which should be integrated into some future alpha
    release.  These patches fix a race condition in earlier NCR5380
    driver cores, as well as fixing support for multiple devices on
    NCR5380 based boards.

    If that fails, you should disable the PSEUDO_DMA option by
    changing the #define PSEUDO_DMA line in drivers/scsi/pas16.c to #undef
    PSEUDO_DMA.

    Note that the later should be considered a last resort, because
    there will be a severe performance degradation.

Section 3.15 : Ultrastor 14f (ISA), 24f (EISA), 34f (VLB)
Ports : 0x130, 0x140, 0x210, 0x230, 0x240, 0x310, 0x330, 0x340
IRQs : 10, 11, 14, 15
DMA channels : 5, 6, 7
IO : port mapped, bus master

Autoprobe : does not work for boards at port 0x310, BIOS not required.

Autoprobe override : compile time only, define PORT_OVERRIDE

Common Problems :
1.  The address 0x310 is not supported by the autoprobe code, and may
        cause conflicts if networking is enabled.

        Please use a different address.

2.  Using an Ultrastor at address 0x330 may cause the system to hang
        when the sound drivers are autoprobing.

        Please use a different address.

3.  Various other drivers do unsafe probes at various addresses, if you
        are having problems with detection or the system is hanging at
        boot time, please try a different address.

        0x340 is recommended as an address that is known to work.

4.  Linux detects no SCSI devices, but detects your SCSI hard disk
    on an Ultrastor SCSI board as a normal hard disk, and the
    hard disk driver refuses to support it.  Note that when this
    occurs, you will probably also get a message

    hd.c: ST-506 interface disk with more than 16 heads detected,
      probably due to non-standard sector translation.  Giving up.
      (disk %d: cyl=%d, sect=63, head=64)

    If this is the case, you are running the Ultrastor board in
    WD1003 emulation mode.  You have

    1.  Switch the ultrastor into native mode.  This is the
        recommended action, since the SCSI driver can be
        significantly faster than the IDE driver, especially with
        the clustered read/write patches installed.  Some users have
        sustained in excess of 2M/sec through the file system using
        these patches.

        Note that this will be necessary if you wish to use any non-
        hard disk, or more than two hard disk devices on the Ultrastor.

    2.  Use the kernel command line switch

        hd=cylinders,heads,sectors

        to override the default setting to bootstrap yourself,
        keeping number of cylinders <= 2048, number of heads <= 16,
        and number of sectors <= 255 such that cylinders * heads * sectors
        is the same for both mappings.

        You'll also have to manually specify the disk geometry when
        running fdisk under Linux.  Failure to do so will result in
        incorrect partition entries being written, which will work
        correctly with Linux but fail under MSDOS which looks at
        the cylinder/head/sector entries in the table.

        Once Linux is up, you can avoid the inconvience of having
        to boot by hand by recompiling the kernel with an appropriately
        defined HD_TYPE macro in include/linux/config.h.

Section 3.16 : Western Digital 7000
Supported Configurations :
BIOS Addresses : 0xce000
Ports : 0x350
IRQs : 15
DMA Channels : 6
IO : port mapped, bus master

Autoprobe :  requires installed BIOS

Common Problems :

1.  There are several revisisions of the chip and firmware.  Supposedly,
    revision 3 boards do not work, revision 5 boards do,
    chips with no suffix do not work, chips with an 'A' suffix do.

2.  The board supports a few BIOS addresses which aren't on the list
    of supported addresses.  If you run into this situation,
    please use one of the supported addresses and submit a bug
    report as outlined in Section 2, "Bug Reports"

Section 4 : Disks

This section gives information that is specific to disk drives.

Section 4.1 : Supported and Unsupported Hardware

All direct access SCSI devices with a block size of 256, 512, or
1024 bytes should work.  Other block sizes will not work (Note
that this can often be fixed by changing the block and/or
sector sizes using the MODE SELECT SCSI command)

Sector size refers to the number of data bytes allocated per sector
on a device, ie CDROMs use a 2048 byte sector size.

Block size refers to the size of the logical blocks used to interface
with the device.  Although this is usually identical to sector size,
some devices map multiple smaller physical sectors (ie, 256 bytes
in the case of 55M Syquest drives) to larger logical blocks or
vice versa (ie, 512 byte blocks on SUN compatable CDROM drives).

Removeable media devices, including Bernoulis, flopticals, and MO drives
work.

Section 4.2 : Common Problems

Section 4.2.1 : Cylinder > 1024 message.

    When partitioning, you get a warning message about "cylinder > 1024"
    or you are unable to boot from a partition including a logical
    cylinder past logical cylinder 1024.

    This is a BIOS limitation.

    See Section 4.4 Disk Geometry and Partitioning for an explanation.

Section 4.2.2 :  You are unable to partition "/dev/hd*"

    /dev/hd* aren't SCSI devices, /dev/sd* are.

    See Section 4.3, Device files, and Section 4.4, Disk
    Geometry and Partitioning
    for the correct device names and partitioning procedure.

Section 4.2.3 :   Unable to eject media from a removeable media drive.

    Linux attempts to lock the drive door when a piece of
    media is mounted to prevent filesystem corruption due to
    an inadvertant media change.

    Please unmount your disks before ejecting them.


Section 4.2.4 : Unable to boot using LILO from a SCSI disk

    In some cases, the SCSI driver and BIOS will disagree
    over the correct BIOS mapping to use, and will result
    in LILO hanging after 'LI' at boot time and/or
    other problems.

    To workarround this, you'll have to determine your BIOS
    geometry mapping used under DOS, and make an entry for
    your disk in /etc/lilo/disktab.

    Alternatively, you may be able to use the "linear" configuration
    file option.

Section 4.2.5 : Fdisk responds with

            You must set heads sectors and cylinders.
            You can do this from the extra functions menu.

        and disk geometry is not 'remembered' when fdisk is rerun.

    See Section 4.4 : Partitioning

Section 4.2.6 : Only one drive is detected on a bridge board with
    multiple drives connected.

    Linux won't search LUNs past zero on SCSI devices which
    predate ANSI SCSI revision 1.  If you wish devices on
    alternate LUNs to be recognized, you will have to modify
    drivers/scsi/scsi.c:scan_scsis().

Section 4.2.7 : System hangs when swapping

    We think this has been fixed, try upgrading to 1.1.38.

Section 4.3 : Device Files

SCSI disks use block device major 8, and there are no "raw" devices
ala BSD.

16 minor numbers are allocated to each SCSI disk, with minor % 16 == 0
being the whole disk, minors  1 <= (minor % 16) <= 4 the four primary
partitions, minors 5 <= (minor % 16) <= 15 any extended partitions.

Due to constraints imposed by Linux's use of a sixteen bit dev_t with
only eight bits allocated to the minor number, the SCSI disk minor
numbers are assigned dynamically starting with the lowest SCSI HOST/ID/LUN.

Ie, a configuration may work out like this (with one host adapter)
Device            Target, Lun        SCSI disk
84M Seagate         0    0        /dev/sda
SCSI->SMD bridge disk 0    3    0        /dev/sdb
SCSI->SMD bridge disk 1    3    1        /dev/sdc
Wangtek tape        4    0        none
213M Maxtor        6    0        /dev/sdd

Etc.

The standard naming convention is

/dev/sd{letter} for the entire disk device ((minor % 16) == 0)
/dev/sd{letter}{partition} for the partitions on that device
    (1 <= (minor % 16) <= 15)

Ie

/dev/sda    block device major 8 minor 0
/dev/sda1    block device major 8 minor 1
/dev/sda2    block device major 8 minor 2
/dev/sdb    block device major 8 minor 16

etc.

Section 4.4 : Partitioning

You can partition your SCSI disks using the partitioning program
of your choice, under DOS, OS/2, Linux or any other operating
system supporting the standard partitioning scheme.

The correct way to run the Linux fdisk program is by specifying the
device on the command line. Ie, to partition the first SCSI disk,

    fdisk /dev/sda

If you don't explicitly specify the device, the partitioning program
may default to /dev/hda, which isn't a SCSI disk.

In some cases, fdisk will respond with

    You must set heads sectors and cylinders.
    You can do this from the extra functions menu.

    Command (m for help):

and/or give a message to the effect that the HDIO_REQ or
HDIO_GETGEO ioctl failed.  In these cases, you must
manually specify the disk geometry as outlined in Subsection
4.5 : Disk Geometry when running fdisk, and also in /etc/disktab
if you wish to boot kernels off that disk with LILO.

If you have manually specified the disk geometry, subsequent
attempts to run fdisk will give the same error message.  This
is normal, since PCs don't store the disk geometry information
in the partition table. In and of itself, will cause _NO PROBLEMS_,
and you will have no problems accessing partitions you created on
the drive with Linux.  Some vendors' poor installation code will
choke on this, in which case you should contact your vendor
and insist that they fix the code.

In some cases, you will get a warning message about a partition ending
past cylinder 1024.  If you create one of these partitions, you will
be unable to boot Linux kernels off of that partition using LILO.  Note,
however, that this restriction does not preclude the creation of a
root partition partially or entirely above the 1024 cylinder mark,
since it is possible to create a small /boot partition below the
1024 cylinder mark or to boot kernels off existing partitions.

Section 4.5 : Disk Geometry

Under Linux, each disk is viewed as the SCSI host adapter sees it :
N blocks, numbered from 0 to N-1, all error free, where as DOS/BIOS
predate intelligent disks and apply an arbitrary head / cylinder /
sector mapping to this linear addressing.

This can pose a problem when you partition the drives under Linux,
since there is no portable way to get DOS/BIOS's idea of the mapped
geometry.  In most cases, a HDIO_GETGEO ioctl() can be implemented
to return this mapping.  Unfortunately, when the vendor (ie Seagate)
has chosen a perverse, non-standard, and undocumented mapping, this
is not possible and geometry must be manually specified

If manual specification of the is required, you have one of several
options :

1.  If you don't care about using DOS, or booting kernels from the
    drive with LILO, create a translation such that heads * cylinders *
    sectors * 512 < size of your drive in bytes (a megabyte is defined
    as 2^20 bytes).


    1 <= heads <= 256
    1 <= cylinders <= 1024
    1 <= sectors <= 63

2.  Use the BIOS mapping.  In some cases, this will mean reconfiguring the
    disk so that it is at SCSI ID 0, and disabling the second IDE drive (if you have one).

    You can either use a program like NU, or you can use the following
    program :

begin 664 dparam.com
MBAZ``##_B+^!`+N!`(H'0SP@=/D\,'5:@#]X=`6`/UAU4(!_`3AU2H!_`P!U
M1(I7`H#J,(#Z`7<Y@,*`M`C-$PCD=3-14HC()#\PY.@R`.@J`%J(\/[`,.3H
M)0#H'0!8AL2Q!M+L0.@7`+K"`;0)S2'#NIP!ZR"ZQ0'K&[K5`>L6N]T!,=*Y
M"@#W\8#",$N(%PG`=>^)VK0)S2'#=7-A9V4Z(&1P87)A;2`P>#@P#0H@("!O
L<B`@9'!A<F%M(#!X.#$-"B1);G9A;&ED(&1R:79E#0HD("`D```````D``!O
`
end

    When run it prints the sectors, heads, and cylinders of the
    drive whose BIOS address was specified on the command line (0x80
    is the first disk, 0x81 the second).

    Ie, dparam 0x80
    60    17    1007

Would mean that C: had 60 sectors, 17 heads, and 1007 cylinders.

Section 5 : CD ROMs

This section gives information that is specific to cdrom drives.

Section 5.1 : Supported and Unsupported Hardware

SCSI CDs with a block size of 512 or 2048 bytes should work.  Other
block sizes will not work.

Section 5.2 : Common Problems

Section 5.2.1 : Unable to mount cdrom.

        The correct syntax to mount an ISO-9660 CDROM is

        mount -t iso9660 /dev/sr0 /mount_point -o ro

        Note that for this to work, you must have the kernel
        configured with support for SCSI, your host adapter,
        the SCSI CDROM driver, and the iso9660 filesystem.

Section 5.2.2 : Unable to eject cdrom.

    Linux attempts to lock the drive door when a piece of
    media is mounted to prevent filesystem corruption due to
    an inadvertant media change.

Section 5.2.3 : Unable to play audio.

    The programs Workman or xcdplayer will do this for you.

Section 5.2.4 :  Workman or Xcdplayer do not work.

    The functions to control audio functions are part of the
SCSI-II command set, so any drive that is not SCSI-II will probably
not work here.  Also, many SCSI-I and some SCSI-II CDROM drives use a
proprietary command set for accessing audio functions instead of the
SCSI-II command set.  For NEC drives, there is a version of xcdplayer
specially adapted to use this command set floating around - try
looking on tsx-11.mit.edu in pub/linux/BETA/cdrom.

    These programs may work with some of the non-SCSI cdrom drives
if the driver implements the same ioctls as the scsi drivers.

Section 5.3 : Device Files

SCSI CD ROMs use major 11.

Minors are allocated dynamically (See Section 4 : Disks, Subsection 4.3 :
Device Files for an example) with the first CDROM found being minor 0,
the second minor 1, etc.

The standard naming convention is

/dev/sr{digit} ie

/dev/sr0
/dev/sr1

etc.

Section 6 : Tapes

This setion gives information that is specific to scsi tape drives.

Section 6.1 : Supported and Unsupported Hardware

Drives using both fixed and variable length blocks smaller than the
the driver buffer length (set to 32K in the distribution sources) are
supported.

Parameters (block size, buffering, density) are set with ioctls
(usually with the mt program), and remain in effect after the
device is closed and reopened.

Virtually all drives should work, including :
    Archive Viper QIC drives, including the 150M and 525M models
    Exabyte 8mm drives
    Wangtek 5150S drives
    Wangdat DAT drives

Section 6.2 : Common Problems

Section 6.2.1 : Tape drive not recognized at boot time.

    Try booting with a tape in the drive.

Section 6.2.2 :  Tapes with multiple files cannot be read properly.

    When reading a tape with multiple files, the first tar
    is successful, a second tar fails silently, and retrying
    the second tar is successful.

    User level programs, such as tar, don't understand file marks.
    The first tar reads up until the end of the file.  The second
    tar attempts to read at the file mark, gets nothing, but the
    tape spaces over the file mark.  The third tar is successful
    since the tape is at the start of the next file.

    Use mt on the no-rewind device to space forward to the next file.


Section 6.2.3 :  Decompression fails.

    Decompressing programs cannot handle the zeros padding the
    last block of the file.

    To prevent warnings and errors, wrap your compressed files
    in a .tar file - ie, rather than doing

    tar cfvz /dev/nrst0 file.1 file.2 ...

    do

    tar cfvz tmp.tar.z file.1 file.2 ...

    tar cf /dev/nrst0 tmp.tar.z

Section 6.2.4 :  Problems taking tapes to/from other systems.

    You can't read a tape made with another operating system or
    another operating system can't read a tape written in Linux.

    Different systems often use different block sizes.  On a
    tape device using a fixed blocksize, you will get errors
    when reading blocks written using a different block size.

    To read these tapes, you must set the blocksize of
    the tape driver to match the blocksize used when
    the tape was written, or to variable.

    NOTE : this is the hardware block size, not the blocking
    factor used with tar, dump, etc.

    You can do this with the mt command -


        mt setblk <size>

    or

        mt setblk 0

    to get variable block length support.

    Note that these mt flags are NOT supported under the GNU version
    of mt which is included with some Linux distributions.  Instead,
    you must use the BSD derrived Linux SCSI mt command.  Source
    should be available from

    tsx-11.mit.edu:/pub/linux/ALPHA/scsi


Section 6.2.5 :  "No such device" error message.

    All attempts to access the tape result in a

    "No such device"

    or similar error message.  Check the type of
    your tape device - it MUST be a character device with
    major and minor numbers matching those specified in subsection
    C, Device Files.

Section 6.2.6 : Tape reads at a given density work, writes fail

    Many tape drives support reading at lower densities
    for compatability with older harware, but will not
    write at those same densities.

    This is especially the case with QIC drives, which
    will read old 60M tapes but only write new 120, 150,
    250, and 525M formats.

Section 6.3 : Device Files

SCSI tapes use character device major 9.

Due to constraints imposed by Linux's use of a sixteen bit dev_t with
only eight bits allocated to the minor number, the SCSI tape minor
numbers are assigned dynamically starting with the lowest SCSI HOST/ID/LUN.

Rewinding devices are numbered from 0 - with the first
SCSI tape, /dev/rst0 being c 9 0, the second /dev/rst1 c 9 1, etc.
Non-rewinding devices have the high bit set in the minor number,
ie /dev/nrst0 is c 9 128.

The standard naming convention is
/dev/nrst{digit}     for non-rewinding devices
/dev/rst{digit}        for rewinding devices

Section 7 : Generic

This information gives information that is specific to the generic
scsi driver.

Section 7.1 : Supported Hardware

The Generic SCSI device driver provides an interface for sending
SCSI commands to all SCSI devices - disks, tapes, CDROMs, media
changer robots, etc.

Everything electrically compatable with your SCSI board should work.

Section 7.2 : Common Problems

None :-).

Section 7.3 : Device Files

SCSI generic devices use character major 21.  Due to constraints
imposed by Linux's use of a 16 bit dev_t, minor numbers are dynamically
assigned from 0, one per device, with

/dev/sg0

corresponding to the lowest numerical target/lun on the first
SCSI board.

Section 8 : Buyers Guide

    A frequent question is:

    "Linux supports quite a number of different boards, so which
scsi host adapter should I get."

    The answer depends upon how much performance you expect or need,
motherboard, and the scsi peripherals that you plan on attaching to
your machine.

    The biggest factor affecting performance (in terms of throughput
and interactive response time during SCSI I/O) is going to be the transfer
type used.

Transfer type    Description / Performance / Recomendedations
Pure        A pure polled I/O board will use the CPU to handle
Polled        all of the SCSI processing, including the REQ/ACK
        handshaking.

        Even a fast CPU will be slower handling the REQ/ACK
        handshake sequence than a simple finite state machine,
        resulting in peak transfer rates of about 150K/sec on
        a fast machine, perhaps 60K/sec on a slow machine
        (through the filesystem).

        The driver also must sit in a tight loop as long as the
        SCSI bus is busy, resulting in near 100% CPU utilitization
        and extremely poor responsiveness during SCSI/IO.
        Slow CDROMs which don't disconnect/reconnect will kill
        interactive performance with these boards.

        Not recommended.

Interlocked    Boards using interlocked polled I/O are essentially
Polled        the same as pure polled I/O boards, only the SCSI REQ/ACK
        handshaking signals are interlocked with the PC bus
        handshaking signals.  All SCSI processing beyond
        the handshaking is handled by the CPU.

        Peak transfer rates of 500-600K/sec through the
        filesystem are possible on these boards.

        As with pure polled I/O boards, the driver must sit
        in a tight loop as long as the SCSI bus is busy,
        resulting in CPU utilization dependant on the
        transfer rates of the devices, and when they
        disconnect/reconnect.  CPU utilization may vary
        between 25% for single speed CDs which handle
        disconnect/reconnect properly to 100% for faster
        drives or broken CD ROMs which fail to disconnect/reconnect.

        On my 486-66, with a T128, I use 90% of my CPU time to
        sustain a throughput of 547K/sec on a drive
        with a headrate of 1080K/sec with a T128 board.

        Sometimes acceptable for slow tapes and CDROMs when
        low cost is essential.

FIFO         Boards using FIFO polled I/O put a small (typically 8K)
Polled        buffer between the CPU and the SCSI bus, and often implement
        some amount of intelligence.  The net effect is that
        the CPU is only tied up when it is transfering data
        at top speed to the FIFO and when it's handling the
        rest of the interrupt processing for FIFO empty conditions,
        disconnect/reconnect, etc.

        Peak transfer rates should be sufficient to handle
        most SCSI devices, and have been measured at up
        to 4M/sec using raw SCSI commands to read 64K
        blocks on a fast Seagate Barcuda with an Adaptec
        1520.

        CPU utilization is dependant on the transfer
        rates of the  devices, with faster devices generating
        more interrupts per unit time which require more CPU
        processing time.   Although CPU usage may be high
        (perhaps 75%) with fast devices, the system usually
        remains usable.  These boards will provide excellent
        interactive performance with broken devices which
        don't disconnect/reconnect (typically cheap CDROM
        drives)

        Recommended for persons on a budget.

Slave          Drivers for boards using slave DMA program the PC's
DMA        DMA controller for a channel when they do a data transfer,
        and return control to the CPU.

        Peak transfer rates are usually handicapped
        by the poor DMA controller used on PCs,
        with one such 8-bit board having problems
        going faster than 140-150K/sec with one mainboard.

        CPU utilization is very reasonable, slightly
        less than what is seen with FIFO polled I/O boards.
        These boards are very tollerant of broken devices
        which don't disconnect/reconnect (typically cheap
        CSG limitDROM drives).

        Acceptable for slow CDROM drives, tapes, etc.

Busmastering    These boards are intelligent.  Drivers
DMA         for these boards throw a SCSI command, the destination
        target and lun, and where the data should end up
        in a structure, and tell the board "Hey, I have
        a command for you."  The driver returns control
        to various running programs, and eventually the
        SCSI board gets back and says that it's done.

        Since the intelligence is in the host adapter
        firmware and not the driver, drivers for these
        boards typically support more features - synchronous
        transfers, tagged queing, etc.

        With the clustered read/write patches, peak transfer
        rates through the file system approach 100% of head rate
        writing, 75% reading.

        CPU utilization is minimal, irregardless of
        I/O load, with a measured 5% CPU usage while
        accessing a double speed CDROM on an Adaptec 1540
        and 20% while sustaining a 1.2M/sec transfer rate
        on a SCSI disk.

        Recommended in all cases where money is not extremely
        tight, the main board is not broken (some broken main boards
        do not work with bus masters), and applications where time
        to data is more important than throughput are not being run
        (bus master overhead may hit 3-4ms per command).

    The second most important driver/hardware feature with respect
to performance is support for scatter/gather I/O.  The overhead of executing
a SCSI command is significant - on the order of milliseconds. Intelligent bus
masters like the Adaptec 1540 may take 3-4ms to process a SCSI command before
the target even sees it.  On unbuffered devices, this overhead is allways enough
to slip a revolution, resulting in a transfer rate of about 60K/sec
(assuming a 3600RPM drive) per block transfered at a time.  So, to maximize
performance, it is necessary to minimize the number of SCSI commands needed
to transfer a given amount of data by transfering more data per command.  Due
to the design of the Linux buffer cache, contiguous disk blocks are not
contiguous in memory. With the clustered read/write patches, 4K worth of
buffers are contiguous.  So, the maximum amount of data which can
be transfered per SCSI command is going to be 1K * # of scatter/gather
regions without the clustered read/write patches, 4K * # of regions
with.  Experimentally, we've determined that 64K is a reasonable
a55mount to transfer with a single SCSI command - meaning 64 scatter/gather
buffers without clustered read/write patches, 16 without.  With the
change from 16K to 64K transfers, we saw an improvement from
50% of headreate, through the filesystem, reading and writing,
to 75% and 100% respectively using an Adaptec 1540 series board.

    Bus type is the next thing to consider, with choices including ISA,
EISA, VESA, and PCI.  Marketing types often spout of absurd bandwidth
numbers based on burst transfer rates and fiction, which isn't very
useful.  Instead, I've chosen to state "real-world" numbers based on
measured performance with various peripherials.

Bus    Bandwidth, description,
ISA    Bandwidth is slightly better than 5M/sec for  busmastering
    devices.  With an ISA bus, arbitration for busmasters is performed
    by the venerable 8237 third party DMA controller, resulting in
    relatively high bus aquisition times.  Interrupt drivers are
    tri-state and edge triggered, meaning interrupts cannot be
    shared. Generally, ISA is unbuffered, meaning the host/memory
    bus is tied up whenever a transfer is occuring. No mechanism
    is provided to prevent bus-hogging.

VESA    Bandwidth is about 30M/sec.  Some VESA systems run the bus out
    of spec, rendering them incompatable with some boards, so this
    should be taken into consideration before purchasing hardware
    without a return guarantee.  Generally, VESA is unbuffered, meaning
    meaning the host/memory bus is tied up whenever a transfer is
    occuring.

EISA    Bandwidth is about 30M/sec, with busmastering operations generally
    being faster than VESA.  Some EISA systems buffer the bus, allowing
    burst transfers to the faster host/memory bus and minimizing impact
    on CPU performance.  EISA interrupt drivers may be either tri-state
    edge-triggered or open collector level-active, allowing interrupt
    sharing with drivers that support it.  Since EISA allocates a
    separate address space for each board, it is usually less prone to
    resource conflicts than ISA or VESA.

PCI    Bandwidth is about 60M/sec.  Most PCI systems implement write
    posting buffers on the host bridge, allowing speed mismatches
    on either side to have a minimum impact on bus/CPU performance.
    PCI interrupt drivers are open collector level-active, allowing
    interrupt sharing with drivers that support it. Mechanisms
    are provided to prevent bus hogging, and for both master and
    slave to suspend a bus-mastering operation.

    Since PCI provides a plug-n-play mechanism with writeable
    configuration registers on every board, in a separate address space,
    a propperly implemented PCI system is plug-and play.

    PCI is extremely strict as to trace length, loading, mechanical
    specifications, etc. and ultimately should be more reliable than
    VESA or ISA.

    In summary, PCI is the best PC bus, although it does
    have its dark side.  PCI is still in its infancy, and although
    most manufacturers have ironed out the problems, there is
    still stock of older, buggy PCI hardware and broken main
    BIOSes.  For this reason, I _strongly_ recommend a return
    guarantee on the hardware.  While the latest PCI mainboards
    are truly plug-and-play, older PCI boards may require the
    user to set options with both jumpers and in software (ie,
    interrupt assignments).  Although many users have
    resolved their PCI problems, it has taken time and for this
    reason I cannot recommend a PCI purchase if having the
    system operational is extremely time critical.

    For many slower SCSI devices, such as disks with head rates
arround 2M/sec or less, CDROMs, and tapes, there will be little difference
in throughputs with the different PC bus interfaces.  For faster contemporary
SCSI drives (Typical high end multi-gigabyte drives have a head rate of
4-5M/sec, and at least one company is currently ALPHA testing a parallel
head unit with a 14M/sec head rate), throughput will often be significantly
better with controllers on faster busses, with one user noting a 2.5 fold
performance improvement when going from an Adaptec 1542 ISA board to a
NCR53c810 PCI board.

    With the exception of situations where PCI write-posting or a
similar write-buffering mechanism is being used, when one of the busses in
your system is busy, all of the busses will be unaccessable.  So, although
bus saturation may not be interfering with SCSI performance, it may have a
negative effect on interactive performance.  Ie, if you have a 4M/sec SCSI
disk under ISA, you'll have lost 80% of your bandwidth, and in an
ISA/VESA system would only be able to bitblt at 6M/sec.  In most cases,
a similar impact on processing jobs in the background would also be felt.

    Note that having over 16M of memory does not preclude using
an ISA busmastering SCSI board.  Unlike various broken operating
systems, Linux will double buffer when using a DMA with an ISA controller
and a transfer is ultimately destined for an area above 16M.  Performance
on these transfers only suffers by about 1.5%, ie not noticably.

    Finally, the price difference between bus masters offered with the
different bus interfaces is often minimal.

    With all that in mind, based on your priorities you will have
certain bus preferences

    Stability, time critical installations,      EISA ISA VESA PCI
        and poor return policies
    Performance, and typical hobbiest        PCI EISA VESA ISA
        installations


     As I pointed out earlier, bus mastering versus other transfer modes is going to have
a bigger impact on total system performance, and should be considered
more important than bus type when purchasing a SCSI controller.

    If will you have multiple devices on your SCSI bus, you may
want to see whether the host adapter/driver that you are considering supports
more than one outstanding command at one time.  This is very
important if you are mixing devices of different speeds, like a
tape drive and a disk drive.  If the linux driver only supports one
outstanding command, you may be locked out of your disk drive while
a tape in the tape drive is rewinding, for example.  With two
disk drives, the problem will not be as noticeable, allthough
throughput would approach the average of the two transfer rates
rather than the sum of the two transfer rates.

Driver feature comparison (supported chips are listed in parenthesis)

Driver                  Simultaneous    SG         > 1
        Transfer mode        Commands    limit        Boards
                    total/LUN
aha152x          FIFO(8k) Polled           1s/1s        255s
    (AIC6260,
    AIC6360)
aha1542       Busmastering DMA     8s/1s        16        Y
aha1740          Busmastering DMA     32s        16
aha274x        Busmastering DMA    4s/1s        1        Y
buslogic    Busmastering DMA    Y        64s, 8196h
fdomain        FIFO(8k) Polled        1s        64s
    (TMC1800,
    TMC18c30,
    TMC18c50)
in2000*        FIFO(2k) Polled        1s        255s
g_NCR5380    Pure Polled         16s/2s        255s        Y
    (NCR5380,
    NCR53c80,
    NCR5381,
    NCR53c400)
gsi8*        Slave DMA        16s/2s        255s
    (NCR5380)
PAS16        Pure Polled        16s/2s        255s        Y
    (NCR5380)    or Interlocked Polled
        (fails on some systems!)
seagate        Interlocked Polled    1s        255s        N
wd7000          Busmastering DMA    8s        1
t128        Interlocked Polled    16s        255s        Y
    (NCR5380)
ultrastor     Busmastering DMA    Y
53c7,8xx    Busmastering DMA    1s/1s        255s        Y
    (NCR53c810)

Notes :
1.  drivers flagged with an '*' are not included with the
    distribution kernel, and binary boot images may be unavailable.

2.  numbers suffixed with an 's' are arbitrary limits set in software
    which may be changed with a compile time define.

3.  hardware limits are indicated by an 'h' suffix, and may differ
    from the software limits currently imposed by the Linux drivers.

4.  unsuffixed numbers may indicate either hard or soft limits.


Board comparison :
Board            Driver        Bus    Price    Notes
Adaptec AIC-6260    aha152x        ISA        chip, not board
Adaptec AIC-6360    aha152x        VLB        chip, not board
    (Used in most
    VESA/ISA multi-IO
    boards with SCSI,
    Zenon mainboards)
Adaptec 1520        aha152x        ISA
Adaptec 1522        aha152x        ISA    $80    1520 w/FDC
Adaptec 1510        aha152x        ISA        1520 w/out boot ROM,
                            won't autoprobe.
Adaptec 1540C        aha1542        ISA
Adaptec 1542C        aha1542        ISA        1540C w/FDC
Adaptec 1540CF        aha1542        ISA        FAST SCSI-II
Adaptec 1542CF        aha1542        ISA    $200    1540CF w/FDC

Adaptec 1740        aha1740        EISA        discontinued
Adaptec 1742        aha1740        EISA        discontinued, 1740
                            w/FDC
Adaptec 2740        aha274x        EISA
Adaptec 2742        aha274x        EISA
Allways IN2000        in2000        ISA
Buslogic 445S        aha1542,     VLB    $250    FAST SCSI-II, active
            buslogic            termination, w/FDC
Buslogic 747S        aha1542,     EISA        FAST SCSI-II, active
            buslogic            termination, w/FDC
Buslogic 946S        buslogic    PCI        FAST SCSI-II, activte
                            termination.
DTC 3290        aha1542        EISA        Although it should work,
                            due to documentation
                            release polcies, DTC
                            hardware is unsupported
DTC 3292        aha1542        EISA        3290 w/FDC
Future Domain 1680    fdomain        ISA        FDC
Future Domain 3260    fdomain        PCI


NCR53c810 (boards sold 53c7,8xx        PCI     $70    chip, not board. Boards
    by FIC, Chaintech,                (board)    don't include
    Nextor, Gigabyte, etc.                      BIOS, although most
    Mainboards with chip by                non-NCR equipped main
    AMI, ASUS, J-Bond,                    boards have the SDMS
    etc. Common in DEC                    BIOS
    PCI systems)

Pro Audio Spectrum 16    pas16        ISA        Sound board w/SCSI
Seagate ST01        seagate        ISA    $20    BIOS only works with
                            some drives
Seagate ST02        seagate        ISA    $40    ST01 w/FDC
Sound Blaster 16 SCSI     aha152x        ISA        Sound board w/SCSI
Western Digital 7000    wd7000        ISA        w/FDC
Trantor T128        t128        ISA
Trantor T128F        t128        ISA        T128 w/FDC and
                            support for high IRQs
Trantor T130B        g_NCR5380    ISA
Ultrastor 14F        ultrastor    ISA        w/FDC
Ultrastor 24F        ultrastor    EISA        w/FDC
Ultrastor 34F        ultrastor    VLB

Notes :
1.  Trantor was recently purchased by Adaptec, and some products are being
    sold under the Adaptec name.

2.  Ultrastor recently filed for Chapter 11 Bankruptcy, so technical
    support is non-existant at this time.

3.  Various Buslogic boards other than the 545S, 445S, 747S, and
    946S _should_ work,  although to my knowledge have not been
    tried.

4.  The $70 price for the busmastering NCR53c810 boards is not
    a typo, includes the standard ASPI/CAM driver package for
    DOS, OS/2 and Windows (32 bit access), and other drivers are
    available for free download.

    If you can't find one at that price, try Technoland at
    1-800-292-4500 or 1-408-992-0888 if you live in California.

5.  Adaptec's recent SCSI chips show an unusual sensitivity
    to cabling and termination problems. For this reason,
    I cannot recommend the Adaptec 154x C and CF revisions or the
    274x series.

    Note that the reliability problems do NOT apply to the
    older 154x B revision boards, 174x A revision boards,
    or to my knowledge AIC-6360/AIC-6260 based boards.

    Also, the quality of their technical support has slipped markedly, with
    long delays becoming more common, and their employees being ignorant
    (suggesting there were non-disclosure policies affecting certain
    literature when there were none), and hostile (ie, refusing to pass
    questions on to some one else when they couldn't answer them).

    If users desire handholding, or wish to make a political statement,
    they should take this point into consideration.  Otherwise, the
    Adaptec 152x/1510 are nicer than the other ISA boards in the
    same price range, and there are some excellent deals on used and
    surplus 154x B revision boards and 1742 boards which IMHO outweigh
    the support problems.

    Most ISA, EISA, and VESA users will probably be served best by
a Buslogic board, due to its performance, features such as active termination,
and Adaptec 1540 compatability.  There are a number of models available with
EISA, ISA, PCI, and VESA local bus interfaces, in single ended and differential,
and 8/16 bit SCSI bus widths.

    People with PCI systems should seriously consider NCR53c810
based boards.  These are bus mastering SCSI controllers, available in
Q1 for about $70 (ie, cheaper than the Adaptec 1520) with larger
quantities being cheaper (I've seen $62 in Q20).  In addition to being
the cheapest PCI SCSI boards, the NCR boards were also benchmarked
as faster than the Adaptec 2940 and Buslogic BT-946, and demonstrate
excellent performance under Linux (up to 4M/sec through the file system )
inspite of the performance optomizations being disabled in the current
driver.  The disadvantages of these boards versus the Buslogics are that
they aren't Adaptec 1540 compatable, don't come with active termination,
and to my knowledge are only supported under DOS+Windows, OS/2, Windows NT,
SCO, NeXTstep, and Free BSD.  Currently, the driver is somewhat
limited, but appears quite stable (We've moved several gigabytes of data to NCR based
devices with no problems), surprisingly fast (I've seen 4M/sec through
the filesystem) and will rapidly become more featureful.

    People wanting non-PCI SCSI on a limited budget will probably be
happiest finding a surplus or used Adaptec 154x B revision or 174x A
revision, or an Adaptec 1520 clone of some sort (about $80) if they want
new.  These boards offer reasonable throughput and interactive performance at a
modest price.

EOF