27 Jul
2004
27 Jul
'04
4:07 p.m.
On Tue, Jul 27, 2004 at 10:46:49PM -0500, Doc Shipley wrote:
Bottom line requirement is that I be able to
low-level format an 8"
floppy to RX02 format. IIRC, RT-11 can flip the switch from RX01 to
RX02 in an RX02 drive, right?
Yes. So can OS/8. The "flip" is when an RX02 drive re-writes part of
the sector to double density. That's what makes them so hard to read
on non-DEC hardware - the media becomes both single and double density.
Both RX01 and RX02 disks start off with "Industry Standard" IBM-compatible
low-level formatting, AFAIK. There are third-party DEC-compatible drives
that can take an absolutely blank disk and lay down tracks. I would think
a suitable CP/M system could do the same. Post-1982 hardware is where
things start to get tricky.
And I need to be able to accurately copy a bootable
RX02 diskette to
a formatted blank.
In terms of development and set-up time, I would think a PDP-11 would
be the fastest way to just dup floppies.
I'd *like* to be able to take a disk image of a
floppy as a file, and
to write that back out to floppy, but that's gravy.
That's trivial with a VAX (BACKUP/PHYSICAL). There must be a way with
smaller hardware (2BSD on a PDP-11, perhaps?)
I wonder what it would take to hook a real RX02 up to modern hardware. The
interface isn't complicated, but AFAIK, it would take more than a PeeCee
parallel port to drive it. Similar to hooking up a real Commodore 1541
to a modern machine and siphoning off a physical backup...
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 28-Jul-2004 03:50 Z
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Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html