Multi-platform distribution format (Was: Backups [was

tony duell ard at
Sun Sep 20 23:52:58 CDT 2015

> 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


> 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.


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