A very simple 8 bit controller from Western Digital
So far I couldn't find any further manuals about this controller on the internet. There is only the usual overview on "Total Hardware 1999".
- ROM BIOS: 0xC8000
- I/O Port: 0x320
- IRQ: 5
Unlike the IT-805 controller, the WD1002S-WX2A has only a very rudimentary low-level formatting routine. 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.
This controller is also kept very simple with regard to the possible settings. There are virtually no jumpers, although the TH99 data sheet mentions some. Actually there are only the jumpers/switches (SW1) for the selection of the hard disks.
Type and number of supported hard disks depends on the BIOS revision. I have the revision X1. This is not mentioned in TH99.
In my case, I just picked the number 0 (REV G) and it fits (SW1/1-4 = 1111). I almost exclusively use the Seagate ST225. The ST225 is actually supported by every controller.
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.
- Total Hardware 1999: Jumpers and switches - Overview