20 Sep
2015
20 Sep
'15
11:50 p.m.
tony duell wrote:
I do have a question here. I got an russian Elektronika 60 (what is
something like an 11/03 clone) and repaired it. Part of that machine is a
russian GMD7012 dual Floppy drive which seems to be a copy of the RX02 too.
All the Disks I've got for that machine are in RX01 Format but while
repairing the Drive I found a jumper in there that is to be used to switch
the Drive from RX01 to RX02 mode.
I've tried to boot an RX01 Floppy in RX02 mode, that failed on all disks
I've tried. Is an original RX02 able to boot (RT11) from an RX01 disk?
I know that a different device driver has to be used normally, but I had
no RX02 media and wasn't able to make one, since the machine has no other
drives connected and the card cage is mechanically not compatible (metric
dimensions including the fingers).
I know that in the RX02 Mode the Drive has an format track command that
doesn't exist in RX01 mode, that's documented. How about the RX02?
Is there somewhere a picture from the Conteroller PCB of the DEC RX02
(just to look at). The russian controller has a 2910 and four 2901 if
I remember correctly... (K1804VU1 and 4xK1804VS1)
Regards,
Holm
--
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For both the DEC RX01 and the DEC RX02 8" floppy drives,
while it might have been possible that DEC engineers were unable
to initially figure out how to allow users to perform an LLF (Low
Level Format) on the 8" floppy drives, it seems certain that after
3rd party manufactures figured out, DEC could also have supported
that function as well.
The controller microcode ROMs in both the RX01 and RX02 are tightly
packed, there is not enough room (IMHO) for a LLF routine. And to use
larger ROMs (certainly in the RX01) would mean some other electronic
modifications.
[...]
After I managed to locate a DSD (Data Systems
Design)
drive which supported the DEC RX02 floppy drive function,
The RX02 can reformat an RX01 as double-density. An RX01 is
essentially IBM3740 format. I have no problems formatting a
blank disk as SSSD in a CP/M machine and then using a (real
DEC) RX02 drive to turn it into a DEC double density disk.
[...]
Note that the RX50 was the same. DEC finally
changed
Not really. The RX01 and RX02 have the controller electronics
in the drive chassis, and that determines what the drive unit
can do (like not doing an LLF). The RX50 is just a bare drive,
the interface is much the same as a PC (say) floppy drive
interface. An RX50 drive, given the right pulses on the
write data line, will most certainly do an LLF. Some DEC
controllers used with it, and some software that used said
controllers might have been unable to do an LLF, but that's
not a problem with the drive.
-tony