5 Apr
2003
5 Apr
'03
3:22 p.m.
OK, this may be obvious to the experts here, but I haven't a clue: can a DEC
RXV21 RX01 / RX02 floppy controller be used with non-DEC floppy drives, using
the standard DEC RT11 driver? By non-DEC I mean ordinary SSSD or SSDD Shugart,
Siemens, or Qume 8" floppy drives.
I recently saw a project where someone uses a Linux PC to act as a RX02 floppy
for a PDP-11 system. That got me thinking: if I can use the RXV21 with foreign
floppy drives, I already have a pair of 8" floppy drives that I could use.
This would be VERY handy and save me some $$$.
OK experts, what is the verdict?
Thanks in advance!
Stuart Johnson
6 Apr
6 Apr
6:06 a.m.
OK, this may be obvious to the experts here, but I
haven't a clue: can a DEC
RXV21 RX01 / RX02 floppy controller be used with non-DEC floppy drives, using
the standard DEC RT11 driver? By non-DEC I mean ordinary SSSD or SSDD Shugart,
Siemens, or Qume 8" floppy drives.
Anything is _possible_ (apart from ski-ing through a revolving door :-)),
but it may not be easy. And using an RX211 or RXV21 or RX8 or ... with
normal drives is certainly not easy.
The reason is that these cards are _not_ floppy controllers. They're bus
interfaces between Unibus/Qbus/Omnibus and a serial link to the drive.
The actual controller is inside the drive chassis -- a board of AMD29xx
bit-slice chips in the RX02 and a board of TTL + microcode PROMs in the
RX01. This controller is responsible for positioning the heads, finding
sectors, doing the CRC, and so on.
Third-party contollers (mostly Qbus) that linked SA800 drives to DEC
machines had a fair amount of logic on the card, often including a pair
of 2901 ALUs and a 2910 sequencer.
-tony
4:22 p.m.
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote:
Third-party contollers (mostly Qbus) that linked SA800
drives to DEC
machines had a fair amount of logic on the card, often including a pair
of 2901 ALUs and a 2910 sequencer.
I have one of those - came in a DataRAM box with a DEC CPU and 3rd party
peripherals (RAM, serial, DQ614, watchdog board). Nice cabinet. Room
for two Tandon TM8xx drives up front (I have one) and a FH 5.25" ST-506
drive buried inside - all before DEC released the BA23, so an embedded
disk was somewhat novel.
I'll have to see what's on the floppy board. I remember attempting to
use it, back in the day. We were trying to format blanks in it with a
low success rate (c. 1985). Turns out there was a cold solder joint
on the TM8xx power connector that finally lifted clean off. I tacked
it back down and it stopped burping.
-ethan
7930
days inactive
7931
days old
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