RZ1000 Data Problems - APAR - PJ19409


               *** IMPORTANT, PLEASE READ THE FOLLOWING ***

If you need to apply any OS/2 2.11 Fixpak up to and including XR_B100, or
OS/2 Warp Fixpak up to and including XR_W009 then you must apply this fix
AFTER the Fixpak is applied.

This fix (PJ19409) will be included in all future Warp and OS/2 2.11 Fixpaks.




Problem Description:

IDE disks can incur possible data read conflicts that can cause data
problems.


OS/2 Versions:

OS/2 2.11 and all versions of OS/2 Warp


Fix Description:

Disable Read-ahead mode for the RZ1000 PCI IDE chip in the OS/2 IBM1S506.ADD
device driver.  This is a generic device driver that will fix all the above
releases and is compatible with non-RZ1000 systems.

The new IBM1S506 device driver detects the RZ1000 and disables read-ahead
only for the RZ1000.  This driver can replace the IBM1S506 on all systems
with IDE interfaces.  A new IBMIDECD.FLT driver is included so as to be
synchronized with IBM1S506.ADD if your system uses this driver.



Performance Impact:

IBM's benchmarks show no system performance degradation by disabling the
RZ1000's read-ahead mode.


Installation Instructions:

1. Save existing IBM1S506.ADD by renaming:

   (For OS/2 Warp)
        > CD c:\OS2\BOOT
        > REN IBM1S506.ADD IBM1S506.RET
        > REN IBMIDECD.FLT IBMIDECD.RET

   (For OS/2 2.11)
        > CD c:\OS2
        > REN IBM1S506.ADD IBM1S506.RET

2. Copy new one:

   (For OS/2 Warp)
        > COPY a:\IBM1S506.ADD
        > COPY a:\IBMIDECD.FLT
        > ATTRIB +R IBM1S506.ADD
        > ATTRIB +R IBMIDECD.FLT

   (For OS/2 2.11)
        > COPY a:\IBM1S506.ADD
        > ATTRIB +R IBM1S506.ADD

3. Re-boot system for the drivers to take effect.


To Verify System Susceptibility to this Problem:

To verify existence of the problem on your system, you may turn on the
verbose option on the new IBM1S506.ADD.  After installing the update per
the instructions above, edit config.sys and add the /V (verbose) switch
option to the IBM1S506.ADD line:

        BASEDEV=IBM1S506.ADD /V

After adding the /V and rebooting your system, if your system displays on the 3rd line of disk information during startup:

   PCI Rev: 02.00  RZ1000 PCI to IDE IC, Rev: 0x01  VID:0x1000 DID:0x1042

then your system does contain an RZ1000 chip and is susceptible to the
above problem.

   Warning: on some systems this message can be displayed for only a brief
            time during system boot.

If no such line appears, then you may revert to the originally shipped device drivers or leave the new drivers installed.

   Note: This fix has no affect on other IDE systems.

Remove the /V option from config.sys if you no longer want the verbose
information displayed.