11 Jan
2012
11 Jan
'12
6:20 p.m.
----- Original Message
Agreed; a confusing term which is why I put it in quotes, but unfortunately
the one folks usually use.
You've obviously seen a much wider variety of disks than I have and I don't
doubt that Cromemco used 'quad' disks somewhere, but I don't think the RDOS
on the FDC supports that format.
The signals that are relevant on the 34 pin connector are in parallel with
the equivalent signals on the 50 pin connector, so the controller doesn't
know or care which connector is being used. The extra 8" signals are not
relevant to the HD drives except for the /RY signal which is not used by
5.25" DD drives like the TM100 but is expected from an 8" drive and thus has
to be jumpered from (50)-22 to (34)-34.
m
Date: Wed, 11 Jan 2012 00:44:13 -0800 (PST)
From: Fred Cisin <cisin at xenosoft.com>
...
I meant that a 1.2M drive is a poor choice to use for
the Cromemco 5.25"
formats, as a substitute for his TM100, because, as you said, it is
really a small 8" drive instead.
It sounded like he was trying to use 1.2M drives for the 400K 5.25"
formats. That CAN be made to work, but introduces a few unnecessary
hassles.
Yes, you're right; it can substitute nicely for an 8" drive but not a 5.25"
DD drive.
If by
80track/double density you actually mean 'quad' density, that's not
really supported although if the drive also rotated at 300RPM instead of
360 then I suppose you could use 1/2 of it as a 360K DD disk.
I have seen 800K "quad" disks from Cromemcos. (I detest the term "quad
density", since it is double density with more tracks, resulting in quad
CAPACITY, but not quad density on the tracks.) If you want to
go to the trouble of making a 34<>50 pin adapter then
you're
good to go; on the other hand, the nice thing about the FDCs is that they
have both 34 pin and 50 pin headers, so as long as you connect the /ready
signal to pin 34 of the 34-pin header you can put all 4 drives on the
same
34-pin cable in any mix of 5.25DD, 5.25HD and 3.5HD .
I had heard (incorrectly?) that the 34 pin connector was only configurable
for the 5.25" data transfer rates (125K, 250K) V the 50 pin connector
being configured for the 8" rates (250K, 500K) >
Is that completely wrong?