🚀 go-pugleaf

In article <DERAADT.91Jun23205834@fsa.cpsc.ucalgary.ca>, deraadt@cpsc.ucalgary.ca (Theo de Raadt) writes:
> Ok, so I see from some old postings that you can hook MFM disks up to
> RQDX3 controllers. What are the differences between these controllers
> (I mean, are they all MFM?).

  Yes, they're all MFM. Assuming you have the latest ROMs in each, the
RQDX1 supports RD51, RD52, RX50. The RQDX2 adds RD53. The RQDX3 adds
RD54, RX33, RD31, RD32, RD33 (which I believe was not marketed).

  The RQDX1 and 2 are essentially the same board - the RQDX1 is an
M8639-YA and the RQDX2 is an M8639-YB (I guess the -00 was a total
loss 8-). The 2 is just a newer circuit layout to attempt to correct
the bus problems in the 1. You can put RQDX2 ROMs in the 1 and run
RD53's. The 1 and the 2 are both 3/1 interleave.

  The RQDX3 is a dual-wide board (M7555) which was done with purchased
technology to fix the performance issues and the high manufacturing
cost of the 1 and 2. It's more intelligent, does 1/1 interleave, and
can (if you whisper the right sweet nothings in its ear 8-) be convinced
to handle non-DEC disks.

  For reference:

  RX33 - Teac FD-55GFR
  RX50 - A DEC-built oddity
  RD31 - Seagate ST225
  RD32 - Seagate ST241-1
  RD51 - Seagate ST-412
  RD52 - Quantum Q540 / Atasi 3046 / [almost] Evotek ET-5540
  RD53 - Micropolis 1325 with jumper R7 inserted (1335 also works)
  RD54 - Maxtor XT-2190

	Terry Kennedy		Operations Manager, Academic Computing
	terry@spcvxa.bitnet	St. Peter's College, US
	terry@spcvxa.spc.edu	(201) 915-9381