Unable to Get into 386 Enhanced Mode with SCSIDISK.SYS

• Microsoft Windows operating system versions 3.1, 3.11

SUMMARY

IBM PS/2 computers equipped with the original IBM hard disk and a Procom MC Enabler SCSI host adapter may have difficulty running Microsoft Windows version 3.1 in 386 enhanced mode.

If Windows 3.1 fails to run in 386 enhanced mode only when the device driver SCSIDISK.SYS is being loaded, this problem can probably be resolved by disabling the MC Enabler SCSI host adapter's direct memory access (DMA) settings.

MORE INFORMATION

According to Procom technical support, the following set of steps should be used to reconfigure the PS/2's DMA settings.

1. Restart the computer from the IBM Reference disk. You must use a copy of the Reference disk that contains all of the proper Adapter Descriptor Files (ADF) for your machine. For more information on ADF files, please see the section below "ADF files".

2. From the Set Configuration menu, choose Change Configuration. Note the current settings under DMA Arbitration Level for both the Procom SCSI Enabler and the other hard disk in the system.

3. Swap the levels of both controllers. For example, if the MC Enabler is set to level 5 and the other hard disk in the system is at level 6, make the MC Enabler level 6 and the existing hard disk level 5.

ADF Files

PS/2 machines come with a write-protected reference disk. In the main menu on this disk, you are prompted to make a backup or working copy of the original disk. This working copy will be customized for one machine.

Any time you add a new system card, such as the Procom's MC SCSI Enabler, the card should come with a disk containing the proper ADF files for that card.

After installing the card you should boot the computer from the backup reference disk. One of the options at the menu is to add ADF files to the working copy of the IBM reference disk. Select the option to update the ADF files and follow the instructions to copy the ADF files from the new disk that came with the card to the working copy of the IBM reference disk. This will allow you to properly configure the card for that particular machine with the new card installed.

For additional information, please contact Procom Technology technical support.

The Procom product included here is manufactured by a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.