Re: Ultima Apple Emulation

[Tom Greene <tom@cowgod.org>]

On Jan 23, 5:47 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> Tom Greene wrote:
> > That is followed by two bytes indicating the number of tracks in the
> > image, then the track data. Each track has a 4-byte header containing
> > the track number (in quarter-tracks) and length. Unused tracks are
> > omitted.
>
> How do you tell that a "track" is unused??
>

The A2V2 imaging program that comes with Virtual II does some kind of
analysis on the data to decide if the track is valid, and the tracks
deemed invalid are not stored in the image. I'm not sure what that
decision is based on.

In practice it doesn't seem to work very well for the few protected
disks I tried. None of the resulting images worked, and for one disk
it even discarded *all* tracks. It works OK for normally formatted
disks, discarding most of the half-tracks.

Tom