CD-ROM Drives

ForceASPI Provides ASPI layer for 98, NT, Me. Many CD burners require this.
DOS & OS/2 Option/Device Driver Diskette

CD-ROM Burning

Guide Rail Dimensions (convert the cheap AT rails!)

External SCSI Devices and POST Errors
MCACDROM (by Brad Parker)
Boot from CDROM?
"Wide" CD-ROM Hangs System or App
DOS Configuration
Modifying W95/98 Install Bootfloppy
OS/2 Configuration
Limits of IBMCDROM
Sound Without a Sound Card?
CD-ROM Audio Connector

External SCSI Devices and POST Errors

Important: Please note that external SCSI devices connected to a standard IBM SCSI adapter will cause POST errors if you unplug them or forget to power them up before turning the system unit on!

For this reason, all non-essential external devices should be set to "Presence error reporting - Disabled" in the Set and view SCSI device configuration menu.

If you want to permanently remove an external device that is no longer connected to the system, enter the Set and view SCSI device configuration menu, find the device in question, and set the "Not present" option to "Remove".


Brad Parker's automated CD-ROM installation for IBM, Adaptec, FD, Buslogic, and Trantor controllers.

Supported by DOS 6.0 and higher, including Win 95/98.

mcacdrom.dsk (not the same contents)
MCACDROM Readme.txt


Term - If the CD is the last device, jumper this to provide termination power
Test - Open for normal use. Open ID1,2,4 and Parity to operate as CD-Audio player mode.
PRV / ALW - Prevent / Allow- Open, Ejects, jumpered, will not eject

For MultiMedia operation set this drive to SCSI-ID 3 for all other select a low priority ID as 4, 3, 2, 1 or 0 and use high priority IDs for fixed-media (for Hard disk use IDs 6, 5 ...)

Termpacks for CD-ROM II

This bad boy uses two F221/331J 305 11-pin resistors.
46xx series spec sheets Bourns 4611X-104-221/331

Personal Preferences For 85s/95s

I use the top 5.25 inch bay if my cabling allows. This keeps the cable from being jammed up against the grilles on the power supply. If you run another SCSI adapter for the CD, you can run a single drop cable to the CD. Better yet if the CD has termination on it- either termpacks or internal termination. This is sweet, because such a setup keeps the SCSI cable from being guillotined while swinging in the power supply. (No in-line terminator hanging off the back).

If you have a CD on a 68- to 50-pin adapter, you have to be careful like when using the in-line terminator. For CDs on a SCSI cable, I'd rather have it between the adapter and the boot drive. That way you can pull it without bothering the termination setup.

Boot from CD-ROM

Many have tried. They all failed. I have tried with my NT 4 CD on my 95A off of a FW. Setup, Start Sequence claims there is no bootable media on the CD.

From Bob Eager:
   I don't think it ever worked except probably with internal IBM CDs. The 'standard' for this wasn't really set when that machine came out. Even now, there's a lot of BIOS incompatibility around.

So much spoofing is required in the BIOS that I doubt it can be made to work. Shame...

SCSI-2 (HPDB68 port) CD-ROM Locks up System

I installed a Plextor PX-20TSi in my 9595 on a wide cable, with the active terminator at the end of the cable. It was the only device on the interior port of the corvette, yet it hung the system when I accessed it a few times.

Cure? Set the Wide Messages" on the internal bus to "Disabled". This sucks when you want to run another fast device on that port as well.

Installing IBMCDROM.SYS (from Peter)

Assumed, you installed an IBM SCSI-Adapter or used the one in your machine (card or onboard) to connect a SCSI CD-ROM drive to it. The adapter is recognized in the setup and so is the CD-ROM drive. But you cannot access it. What's wrong?

Do the following:

  • get the SCSI CD-ROM Driver Disk SCSICDRM.EXE
  • extract it to a 720K / 3.5" disk
  • run the UINSTALL-program from the disk to install the device-driver IBMCDROM.SYS
  • use a Text-Editor to add /i in your CONFIG.SYS at the end of the line with the IBMCDROM.SYS
  • If you have a CD-ROM (like some NEC) and it refuses to work even after adding the /i try to add a /P:2 as well to enable the read seek command on this unit too. (Thanks White Box!)
  • restart the system

This little /i will convince the IBMCDROM.SYS to accept all CD-ROM drives, which do not have the !x-sign in their device descriptor and therefore are recognized as Non-IBM devices. Works fine with NEC, Toshiba, Panasonic, Sony etc.
BTW.: It pays to read the README-file on the SCSICDRM-disk... Pretty easy, right?

Editor's Note: I have had to use the /i switch to get an IBM CD-ROM (first model) to be recognized. But the rebadged Toshiba XM3101BME works under DOS 6.22 and WfW 3.11. Also, a no-brainer is the /D:drivername must be the same in CONFIG.SYS as well as the AUTOEXEC.BAT or you will spend 30 minutes or more looking for a hardware problem that isn't...

DOS Configuration Examples

Sample CD-ROM DOS Configuration (one Drive)


drive:\path\MSCDEX /D:IBMCD001 /M:10


Device=drive:\path\IBMCDROM.SYS /D:IBMCD001 /i

Sample CD-ROM DOS Configuration (two Drives)


drive:\path\MSCDEX /D:IBMCD001 /D:IBMCD002 /M:10


Device=drive:\path\IBMCDROM.SYS /D:IBMCD001 /i
Device=drive:\path\IBMCDROM.SYS /D:IBMCD002 /i


Parameters that effect the DOS - MSCDEX.EXE operation:

/D:drivername Indicates the device driver name. This parameter indicates to MSCDEX.EXE the name to use to locate the device driver. This name must be the same device-driver name given for the DEVICE entry in CONFIG.SYS and the same as that used in the MSCDEX parameter in your AUTOEXEC.BAT.

/L:driveletter Determines what drive letter MSCDEX.EXE uses as the first letter when assigning the CD-ROM-II drive letter. Instead of starting at the first free drive letter MSCDEX.EXE starts at the drive letter specified by this parameter.

/M:value Tells MSCDEX.EXE how much memory to allocate for caching information on the CD-ROM-II. The default value reserves 20KB for sector caching for each drive.

/V Provides memory-use statistics such as how much memory the buffers, resident data, and resident code use.

/E Enables MSCDEX.EXE to use expanded memory for caching information on the CD-ROM-II.

/S Tells MSCDEX.EXE to allow an SCSI CD-ROM drive, installed in a network server, to be shared on an IBM PC Local Area Network (LAN).

W95/W98 Install Boot Floppy Hack

Very simple. You need to put IBMCDROM.SYS and ASPI4B.SYS on the install floppy. Add the blue text to the appropriate files. This assumes that you have one CD-ROM drive as D: and one hard drive as C:

I advise you to put W95's EDIT onto your boot floppy. When you sit there with "Cannot continue, returning to DOS" you will understand why.

My personal preference when infecting a PS/2 with 95 is to put the entire Win95 directory on the hard drive. Then if you somehow mess up the SCSI adapter settings under Device Mangler, you can still get to the CAB files and reinstall things.


Important to use IBMCDxxx! The driver in CONFIG.SYS sets this! If the AUTOEXEC.BAT uses another name or drive number, it won't work.

a:\mscdex /D:IBMCD000 /M:10


menuitem=MCA,Windows95 installation for Microchannel    CD_ROM


Cannot Continue Error

Almost every time that setup dumps you back into DOS (not that you ever left, IMHO) is that the MSCDEX setting in the AUTOEXEC.BAT does not match the CONFIG.SYS line. If you were smart and put EDIT onto the floppy (like I told you) you can open both files and compare the IBMCDROM.SYS line and the MSCDEX lines. It's amazing that a good college education is not enough to make up for typing errors...

OS/2 Configuration Example

Sample CD-ROM OS/2 CONFIG.SYS file (one Drive):

DEVICE=drive:\path\SCSI.SYS /N:4

Sample CD-ROM OS/2 CONFIG.SYS file (two Drives):

DEVICE=drive:\path\SCSI.SYS /N:5

Parameters that effect the OS/2 - CD-ROM operation:

/N: Specifies the number of CD-ROM-II drives in the system.

/Q: Specifies quiet mode for CDFS.IFS. Inhibits messages during startup/installation.

Limits of IBM CD-ROM Drivers

What if IBM CD-ROM drivers do not work?

Peter replies with:
   Err, the ASPI4B driver was *intended* to be used with the ASPICD.SYS ! It simulates the ASPI-layer, which is present on "ordinary" Adaptecs after loading the ASPI4DOS.SYS (on 154x / 164x cards) and the ASPICD-driver is the physical device layer to which MSCDEX later assigns a drive letter to. The IBMCDROM.SYS is worthless in this case - it was intended as a stand-alone device driver *without* any ASPI-compliant manager layer between the hardware (CD-drive) and the software (MSCDEX).

Experience showed, that the combination of ASPI4B + ASPICD often enables "non-working" drives ... but is not necessary on more modern drives. I use a flea-circus of various CD-drives (few are "manufactured for IBM") and use them for Win95-installation for example. And I only have the IBMCDROM.SYS with the additional parameters in the CONFIG.SYS (plus the MSCDEX in the AUTOEXEC of course) - and have no problems. (Ed. My XM3101BME has IBM stickers and Part #s all over it. Hated IBMCDROM.SYS. CDR101 results. Used the Aspi4b driver. It works now. Funny, as it had been working well with the IBM driver in another machine...) 

May well be that it does not work with some older releases of the XM3101 - but the first series IBM CD-ROM II were XM3101 as well ... guess my 77i is currently working with one ... must check.

ASPI4B.SYS vs. ASPIIBM.SYS (from Peter)

As the documents ASPI4B.TXT and ASPIIBM.TXT already explain:

ASPI4B.SYS is a Tool from Adaptec for IBM to transfer "a sort of" ASPI-Manager functionality to the "Spock-like" IBM MCA SCSI Adapter along with the functions of the INT4Bh interface that these adapters normally use.

ASPIIBM.SYS is from Corel SCSI ... and does the same with a lot more parameters. 

Both were originally designed to enable for example SCSI scanners to work with the IBM adapters and using most of the ASPI-based software. My "normal condition" with the Non-IBM CD-ROM drives at the times before the revised IBMCDROM.SYS appeared (and before Win95 made the whole thing a bad joke) was running a CD-ROM. 

CONFIG.SYS contained the two lines:




ASPIIBM.SYS is the Aspi manager layer, ASPICD.SYS is the physical interface device driver using the Aspi command set, MSCDEX is the operation system device driver that routes a drive letter to the device named after /D ...

The ASPIIBM.SYS however shows tendencies to dump Win95 systems into 16-bit mode IIRC - but I found that out at a time where I did not use it anymore. But it is the better driver for e.g. a straight DOS environment / Win 3.x and using scanners, tapes and CD-ROM drives.

Sound Without a Sound Card

> Can I attach an audio plug to the CD Line out connector and run it to an amp?

From Peter:
   Sure can - no problem. Did that with my first CD-ROM drive when I had no soundcard in my old IBM AT back in 1987 or so. The connector has L-G-R (or L-G-G-R or whatever) and is straight analog audio output. The one at the front (if present) is for low-impedance headphones (200 - 1000 Ohms). The rear port is for hi-impedance amplifiers.

> Question is, is the audio there when used in music mode as well as in the program decode mode?

   The audio signal is only present, when there is an audio-CD running in the drive. The "audio" derived from data CDs (e.g. WAV or such) needs a soundcard to convert the digital data packets back to analog signals.

CD-ROM Audio Connector

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

Ardent Tool of Capitalism is maintained by Tomáš Slavotínek.
Last update: 08 May 2024 - Changelog | About | Legal & Contact