One Controller – Four Floppy Disk Drives
Last revision of this chapter: February 9, 2025
This is an IDE hard disk controller with serial and parallel interfaces and two interfaces for a total of four floppy disk drives. Yes, you read that right, four floppy drives. And what can I say, it works perfectly!
If you look at the writing on the FDC IC (DP8473V), then you recognize that this controller supports both FM and MFM and 128 bytes/sector. What more could you want! This FDC is also used by Adaptec in the AHA-1542B.
For an AT 286, this is the perfect card, one slot, four functions: IDE hard disk support, four floppy drives, serial and parallel interface.
I won't go into the IDE component at all, as I have deactivated it in my case (JP6=OFF). I am only interested in the four floppy drives.
I tested the TMC IFSP controller on my IBM XT/286 mainboard with "286-BIOS (c)1989 AMI" BIOS.
As usual, the first two floppy drives A: and B: are accessed via the BIOS and the corresponding selection (360K, 1.2M, 720K, 1.44M), so nothing new. But more is not possible here!
How do you access or set up the third and fourth floppy drives? After a long search on the Internet, I found the driver DC2.SYS, also from TMC. I integrated the driver into the CONFIG.SYS file and then set up the DOS DRIVER.SYS twice. Restart the PC and it works!
CONFIG.SYS
-----
DEVICE=C:\DC2.SYS /ftype1 /ftype2
DEVICE=C:\DRIVER.SYS /C /D:2 /F:1
DEVICE=C:\DRIVER.SYS /C /D:3 /F:1
-----
with ftype1, ftype2 => 360, 1.2, 720 or 1.4
-----
/F:0 => 360
/F:1 => 1.2
/F:2 => 720
/F:3 => 1.44
The fact that the interaction between the controller and the driver works so well for me is probably due to the fact that both are from the same company „TMC“.
But even this statement is not properly confirmed, because the name is given once as TMC and then as T.M.C. Is the same company referred to here? I do not know.
Controller: TMC RESEARCH CORPORATION IFSP (VER. 1.0A)
DC2.SYS: T.M.C. DC2 Version 2.3 Copyright (C) 1989
Update 10/13/2023: I got the following picture from a computer friend. In my opinion, the connection between DC2(.SYS) and IFSP is well illustrated here. Unfortunately, this diskette is no longer readable, according to him.
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