Re: 5.25" disk question

[nparker@cie-2.uoregon.edu (Neil Parker)]

In article <5gkk5p$7a1@nntp1.u.washington.edu> dpeschel@u.washington.edu
(Derek Peschel) writes:
>[...]
>In the PC world, there are formats that are even more ancient than 360K
>(namely, 320K, 180K, and 160K).  I think it may even be possible to
>"roll your own" format by changing the number of tracks/sectors
>per side.
>
>So my question is:
>
>Since the Disk ][ is completely software-controlled (subject to the
>limitations of the hardware in the controller) would it be possible
>to get the Apple to write a disk in some format that a PC could read?
>
>I realize that the capacity would be miniscule; I'm just wondering if
>it would be possible.

Probably not.  As I understand it, those formats differ only as follows:

     Capacity  Sides  Blocks/track
     --------  -----  ------------
       160K      1         8
       180K      1         9
       320K      2         8
       360K      2         9

Other than that, I believe the formats are identical...i.e. they all use
MFM encoding.  The encoding, not the capacity, is the determining factor:
the Apple controller cannot generate the timing necessary to create or read
an MFM data stream.

               - Neil Parker
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