A very simple 8 bit controller from Western Digital
This MFM controller looks almost the same as the WD1002S-WX2A. In contrast to my WD1002S-WX2A it has a lot of jumpers which are not needed because the default settings are used.
The jumpers at W5 (ROM Size) and W7 (IRQ5) are not needed, because PINs 1-2 are hard wired. You can see this when you look at the PCB against the light!
- ROM BIOS: 0xC8000
- I/O Port: 0x320
- IRQ: 5
Unlike the IT-805 controller, the WD1002S-WX2 has only a very rudimentary low-level formatting routine (WX2FMT). You can only select the desired drive and the interleave factor. That was it, unfortunately. See also here
Start low level formatting with:
DEBUG (ENTER) -G=C800:5 (ENTER)
In contrast to the IT-805 (1:1), I can only set the interleave factor to 1:4. More is not possible. I tested both controllers with the same Seagate ST225 and checked them with SpinRite II.
Type and number of supported hard disks depends on the BIOS revision. I have the revision ASD2-0. This is not mentioned in TH99 nor in the OEM manual.
Special note! The drive jumper settings in TH99 are different from the OEM manual!
I just picked the same settings as for the WD1002S-WX2A and it fits (SW1/1-4 = 1111). I almost exclusively use the Seagate ST225. The ST225 is actually supported by every controller.
The two WD1002S-WX2A and -WX2 controllers are compatible, i.e. you can use the same hard disks on both controllers. I set up two ST225 with the WX2A, then changed the controller (WX2) and it works.
In total I have about eight ST225. These hard disks are simply indestructible. The only disadvantage is, they are a little noisy. But on the other hand, that's what makes "Retro Computing" so special.