19 Aug
2022
19 Aug
'22
6:40 p.m.
On Tue, 16 Aug 2022, Bill Degnan via cctalk wrote:
Unrelated factoid. Did you know the Micropolis
1033-II drive is at least
semi-compatible with the Tandy Model 1 Expansion Unit with disk capacity
daugher card / "doubler" setup? Wonder if anyone ever tried this other
than myself.
If you have a 1033-II or similar class drive and you're not sure whether it
works with your VG system it may be possible to test the drive using the
more common TRS 80 expansion interface. Might help differentiate between
the VG controller and the drive as a problem area.
OR, you can test the drive using a R@RE IBM PC/5150!
The TRS80 expansion interface had a "standard" SA400 drive interface.
AND, the TRS80 originally had SA400 drives!
The Micropolis is an SA400 interface.
The Micropolis (lead screw positioner) is SLOW STEPPING. Whereas, the
SA400 had a spiral groove on a small disk, like a vinyl record (not a
database "record"), so, it is SLOW STEPPING. If you need a drive that is
so slow from track to track that it can't get out of its own way, those
two drives are it!
The Micropois I drive is a superb permanent replacement for TRS80.
(SA400 interface, 48tpi, 35 tracks. slow; EXACT replacement)
(note: the bare Micropois drive doesn't mount-up completely easily in the
TRS80 disk drive case)
The MicropolisII can be used on the TRS80, BUT the disks will not
be compatible. BECAUSE the MicropolisII is 100tpi/77 track. Yes, you
could use the first 35 tracks of it, but no interchange of disks.
NEWDOS80/DOSPLUS/LDOS (TRSDOS6), etc. will let you use all 77 tracks.
And, of course, obviously, the TRS80 and VG have TOTALLY different disk
formats.
Other machines that have interface based on SA400, on which you could test
the drive include:
DAMN NEAR EVERYTHING, EXCEPT APPLE, Commodore, and Atari.
Perfect replacement for Northstar (hard sectored)
PC/5150, XT/5160 (160K format, minus last 5 tracks, which will be
presumed "bad")
Any other machine with 5.25" drive that used an SA400, even machines with
""quad density"" (singlesided, and minus last 3 tracks)
(Superbrain/Intertec (without last 3 track), (BUT, ""quad density"".)
(BUT Intertec, after they went to double density, when they added double
sided, they called THAT "quad density". When they went to 80 tracks,
they had already used the name "quad density", so they called 80 track
DSDD "SUPER density", abbreviated "SD" to keep the labelling
confusing))
--
Grumpy Ol' Fred cisin(a)xenosoft.com
.