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			            OS2.TXT
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INSTALLATION GUIDE FOR THE SDMS 8XX OS/2 DRIVER V4.02.00               02/04/97

This file describes the features and use of the Symbios Logic SDMS device 
driver for the OS/2 operating system environment.  It is divided into the 
following sections:

Introduction
     Features of the SDMS OS/2 Driver
     Description of the SDMS OS/2 Driver
Installing Your SDMS OS/2 Driver
     Command Line Options
     Troubleshooting


********************************* Introduction ********************************

The OS/2 operating systems version 3.0 and later provide an integrated platform
featuring a graphical windowing interface, called Presentation Manager, that 
allows multiple applications to be viewed at the same time. Multitasking is 
also supported, enabling several different programs to run at the same time in 
different windows. Presentation Manager allows the user to switch between 
programs, start other programs, and maintain files and directories. These 
versions of OS/2 require an 80386 or higher microprocessor. Other hardware 
requirements include a minimum of 4 megabytes of RAM (8 megabytes or more is 
recommended) and a minimum hard disk drive size of 40 megabytes. Symbios Logic 
SDMS provides the necessary SCSI device driver for OS/2. We recommend reviewing 
the OS/2 manual prior to proceeding.


* Features of the SDMS OS/2 Driver *

Enhances host bus adapter performance
Supports synchronous negotiation (including fast SCSI)
Supports wide SCSI (single-ended and differential)
Supports multiple host adapters
Supports Disconnect/Reselect
Supports scatter/gather
Allows tagged command queuing


* Description of the SDMS OS/2 Driver *

Although the Symbios Logic SCSI controller's firmware can access the SCSI hard 
disk drives attached to the computer independently, the SCSI device driver 
SYM8XX.ADD acts as an enhanced interface between the computer system and the 
SCSI BIOS firmware. Use of the device driver increases the abilities of the 
SCSI controller firmware and fully utilizes the advancements and improvements 
of 80386 and higher microprocessors. 

The device driver is also necessary to support the use of SCSI tape drives and 
CD-ROM drives with an OS/2 system. The Symbios Logic SYM8XX.ADD device driver 
is written in compliance with the IBM OS/2 ADD (Adapter Device Driver) 
specification, and will work with third party applications that comply with the
same specification.


************************ Installing Your SDMS OS/2 Driver *********************

These installation instructions are specific and accurate for the SDMS OS/2 
driver SYM8XX.ADD V4.02.00. You may have a more recent version of this driver. 
You should refer to the text file OS2.TXT located on the SDMS diskette for a 
version of these instructions guaranteed to match your driver.

Note:  If you previously installed OS2CAM.ADD (the previous version of this 
driver), delete OS2CAM.ADD and delete the corresponding BASEDEV= statement in 
CONFIG.SYS after you complete installation procedures. If you previously 
installed SYM8XX.ADD in a directory other than \OS2\BOOT, move SYM8XX.ADD to 
\OS2\BOOT, where the new version of SYM8XX.ADD can replace the old version. 
The system will continue to boot using the previous driver until these steps 
are taken.


* Installing SYM8XX.ADD (with OS/2 already installed) *

The Symbios Logic device driver floppy diskette contains three files, the 
device driver SYM8XX.ADD, a text file, SYM8XX.DDP and an executable file, 
SYMCHECK.EXE. When the device driver installation utility under OS/2 is 
activated it looks for a file with the DDP extension. The DDP file contains 
the necessary information to install the SCSI device driver. The EXE file 
contains a utility that verifies that an appropriate adapter is present.

1) At the OS/2 Desktop, open the System Setup folder located within the OS/2 
   System folder and double-click on the Device Driver Install icon.

2) Insert the floppy diskette containing the Symbios Logic device driver in the
   source drive.

3) Choose the Symbios Logic SYM8XX.ADD driver from the list provided by 
   clicking on it once. The choice will be highlighted. Then click the OK 
   button, then the EXIT button.

4) To make sure that the installation was successful, open the productivity 
   folder on the OS/2 Desktop, then double-click on the OS/2 System Editor to 
   start the editor. Open the CONFIG.SYS file in the root directory and find 
   the line:

   BASEDEV=SYM8XX.ADD /V

   Then check that the file SYM8XX.ADD is in the \OS2\BOOT directory on the 
   boot drive.


* Installing SYM8XX.ADD and OS/2 from a Floppy to a SCSI Hard Drive *

In this case, since OS/2 will be installed from a floppy diskette, it is not 
required that the driver be present to install the operating system (as is the 
case when installing from a CD-ROM).

1) After the installation of OS/2 is complete and the WorkPlace Shell desktop 
   is built, open the System Setup folder in the OS/2 System folder and 
   double-click on the Device Driver Install icon.

2) Insert the floppy diskette containing the Symbios Logic device driver in the
   source drive.

3) Choose the Symbios Logic SYM8XX.ADD driver from the list provided by 
   clicking on it once. The choice will be highlighted. Then click the OK 
   button, then the EXIT button.

4) To make sure that the installation was successful, open the productivity 
   folder on the OS/2 Desktop, then double-click on the OS/2 System Editor to 
   start the editor. Open the CONFIG.SYS file in the root directory and find 
   the line:

   BASEDEV=SYM8XX.ADD /V

   Then check that the file SYM8XX.ADD is in the \OS2\BOOT directory on the 
   boot drive.

5) Continue with the OS/2 installation process as documented in the OS/2 
   Installation Guide.


* Installing SYM8XX.ADD and OS/2 from a SCSI CD-ROM to a SCSI Hard Drive *

To install OS/2 from a SCSI CD-ROM attached to a Symbios Logic host adapter, 
the SCSI driver must be present in order to access the CD-ROM. The following 
steps allow installation of OS/2 from a SCSI CD-ROM.

1) Make copies of the floppy diskettes used for installation that are included 
   with the CD-ROM version of OS/2.

2) Copy the file SYM8XX.ADD from the Symbios Logic distribution diskette to 
   the copy of "Diskette 1". "Diskette 1" does not contain enough available 
   space for a copy of SYM8XX.ADD. You must delete files in order to copy the 
   driver file onto the diskette. If you are installing a version of OS/2 other
   than Warp 4.0, any unused .ADD driver(s) may be deleted. If you are 
   installing Warp 4.0, consult the README.1ST file on the Device Driver Pak 
   Volume 1.0 CD. It contains a list of files that may not be deleted. Follow 
   the instructions provided in the README.1st file.

   When .ADD drivers are deleted from "Diskette 1", make certain to delete or 
   remark out the corresponding BASEDEV= statement in CONFIG.SYS. Otherwise, 
   error messages will show up during installation.

3) Edit the file CONFIG.SYS on the copy of "Diskette 1" by adding the following
   line at the end of the file:

   BASEDEV=SYM8XX.ADD /V

   If you are installing OS/2 Warp 4.0, follow the directions in the 
   README.1ST file for adding the following line to CONFIG.SYS:

   SET COPYFROMFLOPPY=1

   This will allow SYM8XX.ADD to be copied from the installation diskette to 
   the system's boot drive.

4) Place the copy of "Installation Diskette" in the A: drive and reboot the 
   computer.

5) Proceed with the OS/2 installation process as documented in the OS/2 
   Installation Guide.


* Driver Order in the CONFIG.SYS File *

Because of the way OS/2 assigns drive letters, the order in which drivers 
appear in the CONFIG.SYS file is important. The drivers must appear in the 
order in which the drive letters are to be assigned. In particular:

   - OS/2 Warp will install the BASEDEV= line at the beginning of the target 
     system's CONFIG.SYS file regardless of where the line is located in that 
     file on "Diskette 1". You may need to rearrange the order in which drivers
     appear in the CONFIG.SYS file for the target system.

   - If the system is to boot from a hard drive attached to an IDE bus, the IDE
     driver must appear before SYM8XX.ADD in CONFIG.SYS. 

Refer to the OS/2 documentation to fully understand this requirement.


* Command Line Options *

The SYM8XX.ADD driver has several embedded functions which can be accessed via 
switches on the command line in the CONFIG.SYS file. These options are 
described below.


Using the /VERBOSE (or /V) Option:

    Usage:
        /VERBOSE

    This option appears on the command line by default. It enables display of 
    a banner, version number, and SCSI bus information during start up of the 
    system. 

    For example, if you wish to see more detailed information displayed when
    you boot, the line in CONFIG.SYS that loads SYM8XX.ADD should look like 
    this:

    BASEDEV=SYM8XX.ADD /VERBOSE

    or

    BASEDEV=SYM8XX.ADD /V

    To disable this feature, remove this switch from the command line.


Using the /!DM Option:

    Usage:
        /!DM<path[:id]>[,<path[:id]>]*

    Where:
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    This option disables use of the IBM-supplied DASD manager (OS2DASD.DMD) for 
    the devices listed. The DASD manager is used to support direct access 
    devices such as hard drives. 

    For example, if you want to disable OS2DASD.DMD for devices on host adapter 
    0 at target IDs 3 and 5, the line in CONFIG.SYS that loads SYM8XX.ADD 
    should look like this:

    BASEDEV=SYM8XX.ADD /!DM<0:3>, <0:5>


Using the /!SM Option:

    Usage:
        /!SM<path[:id]>[,<path[:id]>]*

    Where:
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    This option disables use of the IBM-supplied SCSI manager (OS2SCSI.DMD) for
    the devices listed. The SCSI manager is used to support SCSI tape drives.

    For example, if you want to disable OS2SCSI.DMD for devices on host adapter 
    0 at target IDs 3 and 5, the line in CONFIG.SYS that loads SYM8XX.ADD 
    should look like this:

          BASEDEV=SYM8XX.ADD /!SM<0:3>,<0:5>


Using the /SYNCH_RATE (or /SR) Option:

    Usage:
        /SYNCH_RATE=n<path[:id]>[,n<path[:id]>]*

    Where:
        n =0, 5, 10 or 20.
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    This sets the maximum synchronous transfer rate (in mega transfers per 
    second) to negotiate with a particular device. The allowable values for 
    this setting are 0, 5, 10 and 20 mega transfers per second, if the adapter
    is capable of the specified speed. All host adapters in the 8XX family 
    support at least 10 mega transfers per second; some support 20 mega 
    transfers per second. To turn off synchronous transfers for a particular 
    device, specify 0 (zero). The value set by this option only defines the 
    maximum transfer rate negotiated. The actual rate also depends on what the
    device can do. The default value is the fastest transfer rate that is 
    supported by a particular host adapter.

    For example, if you want to turn off synchronous transfers to ID=3 on host 
    adapter 0, the line in CONFIG.SYS that loads SYM8XX.ADD should look like 
    this:

    BASEDEV=SYM8XX.ADD /SYNCH_RATE=0<0:3>

    As another example, if you want to set synchronous transfers to 10 mega
    transfers per second on all devices on adapter 1, the line in CONFIG.SYS
    that loads SYM8XX.ADD should look like this:

    BASEDEV=SYM8XX.ADD /SR=10<1>


Using the /SYNCH_OFFSET (or /SO) Option:

    Usage:
        /SYNCH_OFFSET=n<path[:id]>[,n<path[:id]>]*

    Where:
        n = 0..maximum synchronous offset for the adapter.
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    This sets the maximum synchronous offset to negotiate with a particular 
    device. The allowable values for this setting are 0 to the maximum 
    synchronous offset supported by the specified path. The SYM53C8XX 
    controller chips support offsets up to 16. If 0 (zero) is specified for 
    the synchronous offset value, then synchronous transfers are turned off for 
    any specified device. The value set by this option only defines the 
    maximum offset that is negotiated. The resulting rate also depends on the 
    device capability. The default value is the maximum offset that is 
    supported by a particular host adapter.

    For example, if you want to change the synchronous offset to 6 for ID=3, 
    the line in CONFIG.SYS that loads SYM8XX.ADD should look like this:

    BASEDEV=SYM8XX.ADD /SYNCH_OFFSET=6<0:3>


Using the /TIMEOUT (or /T) Option:

    Usage:
        /TIMEOUT=n<path[:id]>[,n<path[:id]>]*

    Where:
       n = time-out value in seconds for device, n=(0..65535), 0=infinite.
       path represents a host adapter ID. 
       id represents a SCSI target ID on the indicated path. 
       [ ]'s indicate optional information.
       * indicates the pattern enclosed in the [ ]'s may be repeated.

    SYM8XX.ADD uses a time-out mechanism to detect certain errors. When 
    SYM8XX.ADD issues a command to a SCSI device, a timer is started. If the 
    timer expires before the command completes, SYM8XX.ADD assumes that 
    something has gone wrong with the device, and takes steps to recover. The 
    default value for this is 10 seconds, and the maximum setting for this 
    switch is 0, which represents no time-out. If you set the value to be less
    than the system has allocated for a particular device, your value will be 
    ignored.

    For example, if you have a particularly slow device on ID=3 and you wish to
    extend the time out on this device to 60 seconds, then the line in 
    CONFIG.SYS that loads SYM8XX.ADD should look like this:

    BASEDEV=SYM8XX.ADD /TIMEOUT=60<0:3>


Using the /DISCONNECT (or /DC) Option:

    Usage:
        /DISCONNECT=n<path[:id]>[,n<path[:id]>]*

    Where:
        n = ON or OFF.
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    SCSI devices have the ability to disconnect from the bus during an I/O 
    transfer. This option is used to allow (or not allow) a device to 
    disconnect during an I/O. If a particular adapter has parity checking 
    disabled, then you must use this option to disable disconnects for all 
    devices on that adapter that do not generate parity. This is because the 
    /PARITY option does not change the disconnect state for any device on that 
    adapter. See the /PARITY option for more information.

    Valid options are "ON" (allow disconnects) and "OFF" (do not allow 
    disconnects). The default for all devices is "ON".

    For example, if you want to disable disconnects on the device at ID=2, then
    the line in CONFIG.SYS that loads SYM8XX.ADD should look like this:

    BASEDEV=SYM8XX.ADD /DISCONNECT=OFF<0:2>


Using the /PARITY (or /P) Option:

    Usage:
        /PARITY=n<path[,path]*>[,n<path[,path]*>]*

    Where:
        n = ON or OFF.
        path represents a host adapter ID. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    The SYM53C8XX chips are capable of enabling or disabling the SCSI bus data
    integrity checking feature know as "parity". Some non-SCSI compliant 
    devices sold as SCSI devices do not generate parity. You can use this 
    option to disable parity checking. The SYMC538XX chips always generate 
    parity (for outputs), but may optionally check the parity (for inputs). 
    Valid options are "ON" (check parity) and "OFF" (do not check parity). 
    The default for all devices is "ON", which enables parity checking for all 
    devices.

    Note: When disabling parity checking, it is necessary to disable 
    disconnects for any device that does not generate parity, as the SYM53C8XX 
    chips cannot disable parity checking for that device during the reselection
    phase. Please refer to using the /DISCONNECT option for more information 
    on how to disable disconnects for a device. If a device does not generate 
    parity and it disconnects, the I/O never completes as the reselection never
    completes.

    For example, to turn off parity checking on host adapter number 0, the line
    in CONFIG.SYS that loads SYM8XX.ADD should look like this:

    BASEDEV=SYM8XX.ADD /PARITY=OFF<0>


Using the /QTAG (or /QT) Option:

    Usage:
        /QTAG=n<path[:id]>[,n<path[:id]>]*

    Where:
        n = the number of queue tags allowed for a device (0..256).
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    Queue tagging is used to allow more than one outstanding command per SCSI 
    device. Some non-SCSI compliant devices sold as SCSI devices do not allow 
    queue tags, in which case queue tagging needs to be disabled. The value 
    given in the command line will be the depth of the queue for queue tags for
    the device(s) indicated. To disable queue tag support, a value of 0 or 1 
    should be given. 

    For example, to turn off queue tagging for ID 3 on host adapter number 0, 
    the line in CONFIG.SYS that loads SYM8XX.ADD should look like this:

    BASEDEV=SYM8XX.ADD /QTAG=0<0:3>

    As another example, if you want to set the queue depth to 5 for all devices
    on host adapter number 2, the line in CONFIG.SYS that loads SYM8XX.ADD 
    should look like this:

    BASEDEV=SYM8XX.ADD /QT=5<2>


Using the /WIDTH (or /W) Option:

    Usage:
        /WIDTH=n<path[:id]>[,n<path[:id]>]*

    Where:
        n = 8 or 16.
        path represents a host adapter ID. 
        id represents a SCSI target ID on the indicated path. 
        [ ]'s indicate optional information.
        * indicates the pattern enclosed in the [ ]'s may be repeated.

    Devices attached to a SCSI bus are narrow or wide devices. Narrow devices 
    transfer data one byte (or 8 bits) at a time. Wide devices transfer two 
    bytes (or 16 bits) at a time. The value given in the command line option 
    will determine the size of data transfers.

    For example, to have the device at ID 3 on host adapter number 0 treated as
    a narrow device, the line in CONFIG.SYS that loads SYM8XX.ADD should look 
    like this:

    BASEDEV=SYM8XX.ADD /WIDTH=8<0:3>

    As another example, if you want to have all devices on host adapter number 
    2 treated as narrow devices, the line in CONFIG.SYS that loads SYM8XX.ADD 
    should look like this:

    BASEDEV=SYM8XX.ADD /W=8<2>


* Troubleshooting *


YOU CANNOT ACCESS THE SCSI DEVICE(S).

Make sure the SCSI device driver is installed properly.

Make sure each device has power.

Verify that a BASEDEV = SYM8XX.ADD /V line exists in the CONFIG.SYS file. 

Verify that SYM8XX.ADD is in the appropriate directory (\OS2\BOOT).

Check the cable connections and the host adapter installation.


THE COMPUTER HANGS OR LOCKS UP WHEN BOOTING AND THE SCSI DEVICES ATTACHED ARE 
NOT SEEN BY THE COMPUTER SYSTEM.

Make sure that all the SCSI devices are configured at different ID numbers (the
boot drive must have the lowest ID).

Make sure both, but only, the ends of the SCSI bus are terminated.

Make sure the device driver is listed in CONFIG.SYS (and loaded when booting).


THE DEVICE DRIVER DOES NOT SEE ONE OF THE SCSI DEVICES.

Reboot the computer.

Make sure the SCSI devices have different ID numbers (the boot drive must have 
the lowest ID).

Make sure both, but only, the ends of the SCSI bus are terminated.

Check the cable and power connections.


OS/2 INSTALLS TO AN IDE DRIVE IN THE SYSTEM INSTEAD OF INSTALLING TO THE 
SCSI DRIVE.

The IDE drive must be physically disconnected and disabled in the CMOS setup 
before attempting to install to a SCSI drive.


THE FOLLOWING MESSAGE IS DISPLAYED AT BOOTUP.

     "OS/2 is unable to operate your hard disk or diskette drive. The system is
     stopped. Correct the preceding error and restart the system."

This problem is caused when your system is booting from a hard drive attached 
to an IDE bus, a SCSI disk is attached to your SYM8XX host adapter, and the 
statement 

     BASEDEV=SYM8XX.ADD /V 

appears in the CONFIG.SYS file before the IDE device driver statement.

Boot the system using the floppy drive and installation diskettes to the 
F3=Command Prompt screen. Use the tedit.exe editor to edit the CONFIG.SYS file.
Move the BASEDEV=SYM8XX.ADD /V statement to the last line in the CONFIG.SYS 
file.

Restart your system. 


DURING MODERATE TO HEAVY I/O LOADS THE MACHINE HANGS

If you are running OS/2 Warp SMP on a multi-processor machine, IBM has 
published an errata which may affect your system. On some multi-processor 
platforms, during moderate to heavy I/O loads, the machine will hang. This 
hang is due to a configuration problem between the machine and OS/2's SMP 
program, OS2APIC.PSD. In order to keep this from happening, we suggest that 
you add the following command line option exactly as shown to the PSD= line in 
the CONFIG.SYS file.

Old line:
PSD=OS2APIC.PSD

New line:
PSD=OS2APIC.PSD /prec=lid

The /prec=lid text IS case-sensitive, make sure you use lower case letters and 
do not add any spaces to the example. This will keep your machine from 
encountering the hang condition.
