Last revision of this page: February 5, 2025

In part 1 I still had a configuration with the CompatiCard as 1st and only floppy disk controller in an AT system. That was not correct! Now I rebuilt the system and added a 2nd floppy disk controller. I also added two more floppy disk drives

Mainboard

The mainboard looks simply great and is only minimally damaged by an old leaking NiCd battery. The tracks were cleaned and sealed again by the seller. Well done.

Configuration, BIOS, etc.

• 286-BIOS (C)1989 AMI (with ROM diagnostic)
• 1,024 KB RAM
• MS-DOS 3.20
• Disk drives
• # A: 1.2 MB, 5,25" / TEAC FD-55GFR
• # B: 360 KB, 5,25" / TEAC FD-55BV
• # C: 20 MB / Seagate ST225
• # D: 1.44 MB, 3,5" / TEAC FD-235H
• # E: 8" / Mitsubishi M2896-63
• # F: UniForm (user-defined)
• Controller (1st) / Western Digital WD1006-MM2
• # FDC: WD37C65B / FM(SD) compatible
• # HDC: WDC42C22
• Controller (2nd) / CompatiCard I, Rev B
• # FDC: P8272A

My favourite 16 bit controllers are the Western Digital WD1003-MM2 and WD1006-MM2. They are fast (Interleave 1:1) and always work. Since I use several 16 bit computers, I can also exchange the hard disks without any problems. Sometimes I also use the -MM1 variant when I only want to connect a hard disk and no floppy.

Drive D and E are added via the CompatiCard driver. You don't have access to them without CCDRIVER.SYS. Drive F is user-defined by UniForm-PC and added by UNIFORM.SYS. My both default types are MS-DOS Standard [DSDD:8":DOS] or Standard CP/M [SSSD:8":CPM].

I am using version 1.27 (August 7, 1989) and everything is fine. I have no problems. There are versions 2.02 (March 31, 1992) and 2.03, but these are for the CompatiCard II and IV.

I have searched on the internet for a long time, but there seems to be only version 1.27 for the CompatiCard I.

Since I operate the 1.2 MB and 360 KB floppy disk drives via the primary WD controller, the CompatiCard must be configured as an add-on secondary controller.

CompatiCard I is not a replacement for the primary floppy disk controller in an AT type machine. [User Manual, 3rd Ed., March 1990, p. 1-1]

I have set up the CompatiCard as „third“ controller (J1=A, J2=B, I/O Port: 360h-367h) with the internal drive adresses 8 to 11.

If you are not using CompatiCard as the primary AT controller, you may choose any of the three remaining address jumper settings. Pick one which works in your computer. The third (A, B) has been found to work in most cases. [User Manual, 3rd Ed., March 1990, p. 2-1]

CompatiCard and UniForm Software Configuration

device=c:\...\ccdriver.sys /8,7,3 /9,4,10
device=c:\...\uniform.sys

Use the CTRL-D keys to select your default format. Use the CTRL-I keys to format (initialize) a floppy disk with the selected format.

If you type the command "CCDRIVES" after the DOS prompt, you get the following message:

C:>ccdrives

CCDRIVES Version 1.27

The following CompatiCard drives are avaliable:
Drive D: - 3.5 inch High Capacity
Drive E: - 8 inch

UniForm-PC Drive F set to: MS-DOS Standard [DSDD:8":DOS]
C:>

To my knowledge, UniForm-PC is the only way to operate an 8 inch drive with the original MS-DOS format of 77 tracks, 1024 bytes per sector and 8 sectors per track.

Norton DI-Disk Information now correctly specifies the disk parameters. Also the media decriptor is correctly specified with FEh! The "system id" indicates that this disk was initialized (formatted) with UniForm-PC.

At bitsavers.org I downloaded the image of MS-DOS 2.11 for the NEC APC. On my test PC I copied the image with Dave Dunfields ImageDisk to an 8 inch floppy disk. While copying I noticed the floppy disk parameters: 1,024 bytes/sector, 8 sectors and 77 tracks! Then I selected the NEC APC 8" format with UniForm and ... see there ...

Notice anything? I have executed the CAT.COM file and it is actually executable! In other words: I was able to run a file for the NEC APC (MS-DOS 2.11) on my IBM compatible AT under Ms-DOS 3.20. But the program CAT.COM works only in connection with the 8 inch drive.

Another test. I copied the program CIPHER.COM to my hard disk C: and started it. This also works. I was able to encrypt a text file and then decrypt it again. You can hardly believe it!

• Part 1: CompatiCard I
• Part 2: Testing the 8 inch floppy drive options
• Part 3: My CompatiCard PC (80286 AT)
• Part 1: CompatiCard IV