[Coco] Re: Disk drive questions?

[Theodore A. Evans]

On 12/04/03, jdaggett at gate.net wrote:
> Jim
> 
> If I remember correctly yes you can have two disk controllers in the MPI.
> Drive 0 must be in the first slot. Also, if my memory serves me
> corrrectly, you can have four single sided drives or two double sided
> drives or two single sided and one double sided drive. So yes three
> physical drives are the max allowable if one is the double sided otherwise
> four.

Whatever the 1773 and 1793 were designed to do, as implemented in the
CoCo they support 4 single sided using all three select lines for
drive select, or 3 double sided using three lines as drive elect and
one as side select.  The controller is flexible enough so that it is
possible to actually possible to control the state of all for lines
independantly, so concievably you could decode to 15 or 16 sides
(depending on whether you treated 0 as a selection).  In addition when
the first 5v controllers (1773) came out there was at least some
trouble with copy protected software not working any more because they
failed to read track one because it was formatted as single density.

Using a 1773 based controller, I have three double sided drives, and
commonly use one of these with disks holding 738k (755,712 bytes) on a
disk or 369k (377,856 bytes) on a side.

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