🚀 go-pugleaf

In article <wV8JX4w163w@zl2tnm.gp.co.nz>, don@zl2tnm.gp.co.nz (Don Stokes) writes:
> 
> Does anyone know how format a disk to look like an RX50?  Can a PC high
> density floppy drive do it?   With DOS?

 Yes. Yes. Sort of.

 Out-of-the-[DEC]-box RX50 diskettes are a bit strange. The gaps are tight
enough that a PC's controller chip (NEC uPD765 or clone) will have some
problems. I've formatted diskettes on a PC and been able to read them in an
RX50 drive, but I wouldn't bet on it always working.

  What _does_ work is a Central Point Software COPY II PC Option Board. This
is a hardware add-on used for copying "uncopy-able" diskettes. You need to
patch the drive tables so it won't double-step the heads (since an AT-type
80-track drive must double-step to copy a 360Kb PC diskette). One you've
done that, set the Option Board up for 80 tracks, single-sided, keep track
length and go make the copies. Avoid using RX50's that say "Format Copyright
Digital Equipment Corp" as masters 8-).

  Of course, there are other options. A Rainbow can format RX50's. Several
3rd-party controllers for Q-bus do as well (the Andromeda UDC11 comes to mind).

  Probably the best solution is to upgrade the RX50 to an RX33 drive, which
gives you 3x the capacity and is user-formattable. Some PDP-11 operating sys-
tems (like RSTS/E) allow formatting the disks without needing diagnostics.
[Guess where the RSTS/E group got that idea... 8-]

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