ImageDisk and some 8" images posted - test-drb@ccmp.vtda.org

3 Aug 2005

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Subject: Re: ImageDisk and some 8" images posted
   From: Dave Dunfield <dave04a at dunfield.com>
   Date: Wed, 03 Aug 2005 05:58:03 -0400
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

   IIRC, the
Ensoniq Mirage had mixed sector sizes. 
Hey... I have one of those - it used to belong to my mother (she was a
professional musician).

I'd love to have a way to image disks for it.  I think I remembered
the disks were wierd, but not how they were wierd. 
Unfortunately it's looking like mixed sector sizes within one track are
not within the capabilities of the 765 to write - although I could probably
READ them OK (and with a documented image file format, you would at least
have access to the data so you could try to find some other way to recreate
the disks if you had to). 
Dave there is a trick.

Looks at FCOPY at Gaby's (unoffical CPM archive).  Tim and I developed it
for a project and it's not a generic imager.  However we found a few things
out and one is that most 765 implmentations will lock up if in the worng 
mode (SD or DD) initially. So to do mixed sector you can't write.  However 
reading is possible if you first try the mode that doesnt lock first then
switch.

In the end you will be recreating the catsweasel.  If you really want to 
go to the next level starty with a PC fast enough and skip the whole FDC
chip thing.  The next level is a data speperator logic and a shift
register that can be read at the bit rate by the PC and do the needed
pattern regognition (look for sync, address marks and the like), and then
build a literally imaged disk and that can be anaylysed.

Allison