> From: Paul Koning >> On Dec 31, 2018, at 6:32 PM, Henk Gooijen via cctalk <cctalk at classiccmp.org> wrote: >> ... >> There are one or two bits in a register of the RK11 that have a >> different meaning/function, depending on the controller being a -C or >> -D.
> If someone can point me to the description of the differences I should > be able to say what RSTS will do with them. AFAIK, the only difference (in programming terms) between the -C and -D is that the -D has dropped the maintainance register. Although I cheerfully admit I haven't sat down with -C and -D manuals and done a bit-by-bit compare. I just did that (I used the "RK11-C Moving Head Disk Drive Controller Manual", DEC-11-HRKA-D, and the 1976 "Peripherals Handbook"), and found in the following: In the RKDS: bit 7 has changed the definition slightly ("Drive Ready" to "R/W/S Ready"), but seems to be basically the same. In the RKCS, bit 9 is "Read/Write All" in the -C, and unused in the -D; bit 12 is "Maint" in the -C, unused in the -D. In other words, a -D driver should work just fine with a -C, IMO. Noel