Configuring Adaptec SCSI CD-ROMs on DOS


I’ve been experimenting with various CD-ROMs in my Am386’s cute but weird AT case. The vertical orientation makes traditional tray loading drives difficult to use, even ones sporting those special clips. I found a slot-loading SCSI Pioneer drive that might do the trick, so this weekend I set about configuring it.

View all posts in the Am386 series
A cool Adaptec AHA-1542CP ISA SCSI card

Photo showing the SCSI drive sitting on its side and connected.

Sourcing drivers

Adaptec’s site still maintains downloads for all their classic ISA SCSI cards, which is frankly incredible. This is the download page for my AHA-1542CP, but you can search to find your specific model.

Microchip: AHA-1542

Once you download the drivers and extract to a floppy, you’ll need to install the ones appropriate for your card. Check the included docs and note whether you need ASPI2DOS.SYS or ASPI4DOS.SYS. Worst case scenario, you can try both and see which works.

These work great for me, I’ve read some people having issues with these 2000-era drivers. This page on the Internet Archive has older versions you can try:

Collection of Useful DOS Drivers

You’ll also need a copy of MSCDEX.EXE which you can get from most classic Windows boot disks. Extract all these to a local directory, such as C:\DRIVERS.

Installing drivers

Open CONFIG.SYS and add these lines:

  1. The /P switch for ASPIxDOS.SYS refers to the IRQ for your Adaptec SCSI card: 330h is the default, but you can see what your card uses by pressing CTRL+A when your machine boots to enter the Adaptec SCSISelect tool.

  2. The /D switch for ASPICD.SYS is a unique identifier.

  3. ASPIBUF.SYS is needed for machines with more than 16 MiB of memory. My 386 maxes out at 8 MiB, so I have it commented out.

Then load MSCDEX in AUTOEXEC.BAT with this identifier:


My personal experience is that the regular MSCDEX replacements we all use for IDE drives don’t work with SCSI, but you may have better luck.


If the drivers worked, you should see output similar to this:

AHA-1540/1542/1640 ASPI Manager for DOS
Version 3.36S
Copyright 1989-1997 Adaptec, Inc.
ASPI4DOS.SYS Installation Successful
ASPI CD-ROM Driver for DOS
Version 4.01S
Copyright 1990-1996 Adaptec, Inc
   Host adaptor 0, Target SCSI ID = 4 - LUN 0: Pioneer CD-ROM DR-U16S  1.01
CD-ROM driver installed: 1 host adapter(s),  1 target(s)
MSCDEX Version 2.25
Copyright (C) Microsoft Corp. 1986-1995. All rights reserved
       Drive D: = Driver PIONEER unit 0

From now on, the CD-ROM will behave the same as any IDE drive in DOS or Windows, albiet a bit faster if you were like me and using one of those Multi-IO cards before.

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