CDOSGEN question

[Martin Eberhard]

I suppose you can spot the newbies by all the dumb questions...

How do I tell CDOSGEN that I have a fast-seeking Persci drive (connected to a 16FDC)? The version of CDOS that I am running is 2.54, and as it came, the Persci drives seek at full speed. However, if I generate a new CDOS with CDOSGEN version 2.54 (using CDOSGEN from the same disk as CDOS), the fastest seek choice is 3mS, which is very slow for a Persci, and sounds horrible. The other seek speed choices are worse. Is there a patch to tell this version of CDOSGEN to seek at Persci's full speed?

See below for the CDOSGEN dialog.

I find this to be strange, because Cromemco was one of the first adopters of the Persci drives, and supported them for a long time. And even more strange because the version of CDOS on the disk works correctly with the Persci drives.

I know that Persci drives seek a little differently than other floppies - they are more like hard drives. For most floppies, software or the disk controller chip sends step pulses at a predetermined rate, and then waits a predetermined settling time before accessing the disk - completely open loop. But with Persci drives, the software/disk controller chip sends seek pulses as fast as it can with no delays, and the Persci drive responds with a "Seek Complete" signal when on track.

This makes me think there ought to be a separate option somewhere in CDOSGEN for the Persci drives.

Suggestions?

Thanks - CDOSGEN dialog follows.

A.CDOSGEN

CDOSGEN version 2.54
Cromemco Disk Operating System Generator
Copyright (c) 1978, 1982 Cromemco Inc.

Memory size (3FFF through FFFF or 16K through 64K) <FFFF or 74K> ? FFFF

Drive A type (S = Small, L = Large) ? L
      Seek speed (1 = 3mS, 2 = 6mS, 3 = 10mS, 4 = 15mS) <1> ? 1
      Single or Double sided <D>   ? S
      Single or Dual density <D>    ? S
Drive B type (S = Small, L = Large, H = Hard, N = None, E = End) ?

==== etc. =====

[MikeS]

----- Original Message -----

From: Martin Eberhard

To: crom...@googlegroups.com

Sent: Thursday, August 25, 2011 9:26 PM

Subject: CDOSGEN question

I suppose you can spot the newbies by all the dumb questions...

 

Not a dumb question at all; 2.54 added support for the Tandon 8" TM848s and subsequently 2.54 and 2.56 no longer handled the PerScis correctly; this was apparently fixed in 2.58, but that doesn't explain how or why your original version of 2.54 works correctly...

 

mike

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[Martin Eberhard]

With some difficulty, I got 2.58 running. I was only able to find an
IMD image of 2.58 on 5.25" disk - so I rigged such a disk to my Z-1.
But... my boot ROM is too old to boot from a 5.25" disk. So I had to
use the old 2.54 version of CDOSGEN to make a version of 2.54 that
supports a 5.25" disk on drive C, then load the files from drive C
onto an 8" disk in B, then run the new CDOSGEN to create a version of
2.58 that knows about Persci drives and 5.25" drives. Long way
around...

But you were right - I can set the step rate to 1 mS with 2.58, which
mostly works right with the Persci drives. It still restores at a very
slow step rate, whereas older versions of CDOS restored quickly,
taking advantage of the restore ability of the Persci drive. Not a big
deal. But it would be nice to have the Persci drives work perfectly
with CDOS 2.58. Is the source code out there anywhere?

I am pretty sure there was a patch to make the Persci drives work well
with CDOS - evidence is the version of 2.54 that I found - that works
perfectly with the Persci drives.

Thanks for the tip about 2.58.

Martin

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