15 Jan
2005
15 Jan
'05
5:13 a.m.
From: John Allain [mailto:allain@panix.com]
Sent: Saturday, January 15, 2005 9:59 AM
You're
correct about disassembly. It was much easier than I thought. The
biggest problem was getting to the drive mounting bolts on the side by the
expansion cards. After removing all the cards, there was just enough room
for a socket and ratchet to fit in there.
Any suggestions or comments in general about this
machine?
I gave myself 30 minutes to get one of those going once.
I got access to just about all subsystems/components in that time.
The coolest thing that really made me like the machine was that the
video monitor was IIRC 5V,NTSC in, picture out. Very easy to use. - - -
You might want to try Rewriting fresh floppies on a true 360K drive,
heat,time, and 1.2M drives all can degrade the data to some degree.
I do use a 360K drive in my 486 just for creating these discs. I guess I
wasn't clear on this.
Now, by disassembling and cleaning the B: drive, I was able to get the
machine booting off this drive (cabled as A:). However, the same cleaning
procedure on the A: drive did not allow it to boot. I still have to clean
the heads. Maybe that'll make a difference. If not, I think I may have other
Qume drives without the IBM monniker on them that I can swap the bezels
with. I just have to dig through the cabinent and see what'll fit.
John A.
Thanks,
Kelly
15 Jan
15 Jan
8:59 a.m.
Now, by disassembling and cleaning the B: drive, I was
able to get the
machine booting off this drive (cabled as A:). However, the same cleaning
procedure on the A: drive did not allow it to boot. I still have to clean
the heads. Maybe that'll make a difference. If not, I think I may have other
Qume drives without the IBM monniker on them that I can swap the bezels
with. I just have to dig through the cabinent and see what'll fit.
THe early, original Qumetrak 142 drives have my nomination for the second
to worst drive ever, coming in right after the early versions of the BASF
2/3 height drives.
The Qume drive was SO slow, that PC-DOS 2.10 had to extend the times to
prevent timeouts on normal disk I/O.
9:31 a.m.
The early, original Qumetrak 142 drives have my
nomination for the second
to worst drive ever, coming in right after the early versions of the BASF
2/3 height drives.
The Qume drive was SO slow, that PC-DOS 2.10 had to extend the times to
prevent timeouts on normal disk I/O.
Shugart developed a much worse drive that thankfully never made it into
production. It was assembled on a bent-metal frame instead of a casting,
and instead of a stepper motor for head positioning, it used a mechanism
similar to an 8-track tape. Each step pulse advanced the head position
by one track, but only in one direction, and it was *incredibly* slow.
Once you got to the last track (I'm not sure if that was 34 or 39), the
next step pulse would return the carriage to track 0, which took even
longer.
This was intended to be a very low cost drive, but would have required
software changes since disk controller chips and normal software expect
to have bidirectional seek.
We played with a prototype for a few hours and decided that our
customers wouldn't want it.
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