Resolved: on-disc data for Tynesoft 5-sector tracks

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scarybeasts
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Resolved: on-disc data for Tynesoft 5-sector tracks

Post by scarybeasts » Thu Mar 26, 2020 9:29 am

Hi,

[Splitting out from the FSD archiving mega thread: viewtopic.php?f=6&t=18668]

Finally got my hands on a Tynesoft title with the "interesting" protection -- Winter Olympiad. It has the 5-sector tracks with sectors of 1024, 1024, 512, 256 and 128 bytes. An open question was how does it squeeze all those bytes on to the 3125 byte track, what with all the inter- and intra- sector gap requirements etc. Turns out, as suspected, the gaps are shrunk down dramatically in places where the disc controllers are tolerant of such a thing.

[Definition: 12/5 means 12x bytes of FF and 5x bytes of 00, for 17 total]

The intra-sector gaps, aka. GAP2, are mostly left alone because the disc controllers don't put up with any nonsense here. These are normally 17 bytes [11/6] and are found as [12/5] or [12/6] on the track.
The inter-sector gaps, aka. GAP3, is where the fun is. These might normally be [21/6] or [16/6]. Tynesoft have used, in order of the 4 inter-sector gaps, [1/3] [1/6] [0/7] [1/6].
With such severely chopped GAP3, the rest of the track is positively roomy, leaving ~20 bytes for GAP1 + GAP4.


I consider this the last of the big protected disc layout mysteries. So I'll be moving on to converting @billcarr's FSD archive to HFE files and publishing them. HFE files can be used verbatim with a FlashFloppy+Gotek to enjoy protected titles as they were originally experienced; or converted to a low level format to be re-written to a real floppy.


Cheers
Chris

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leenew
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Re: Resolved: on-disc data for Tynesoft 5-sector tracks

Post by leenew » Thu Mar 26, 2020 11:34 am

Excellent =D>

Lee.

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vanekp
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Re: Resolved: on-disc data for Tynesoft 5-sector tracks

Post by vanekp » Thu Mar 26, 2020 4:28 pm

=D> =D> =D> Look forward to them :wink:
Peter.

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