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Re: DSK format specification
- Subject: Re: DSK format specification
- From: Andy McFadden <fadden@fadden.com>
- Date: Mon, 14 Jul 2003 15:58:17 GMT
- Newsgroups: comp.sys.apple2
- Organization: faddenInternet, Inc.
- References: <rLOPa.250$Y%3.201@nwrddc03.gnilink.net> <lr0Qa.1241$dk4.53908@typhoon.sonic.net> <ber74a$dqo$1@merope.saaf.se> <S_gQa.1437$dk4.64825@typhoon.sonic.net> <betsce$1amk$1@merope.saaf.se>
- Sender: Andy McFadden <fadden@adsl-209-204-141-120.sonic.net>
- User-agent: tin/1.4.7-20030322 ("Suggestions") (UNIX) (Linux/2.4.20-8 (i686))
- Xref: archiver1.google.com comp.sys.apple2:32856
Paul Schlyter <pausch@saaf.se> wrote:
> The structure and contents of the CP/M system tracks are indeed
> completely implementation specific. It doesn't even have to be 3
> tracks: om the classic CP/M disk format (8" SSSD) the system tracks
> were only 2 tracks; otoh each track on 8" SSSD disks contained more
> than each track on an Apple II 5.25" disk.
[... lots of stuff removed ...]
So it sounds like a program that processes disk images needs a set of
DPBs, from which it chooses one based on the physical characteristics of
the drive. For the Apple II world there are separate DPBs for 13-sector
and 16-sector disks.
> Above the BIOS level, the file system area (i.e. everything except
> the system tracks) on the disk are regarded just as a data area of
> some specific size. CP/M doesn't care where a new tracks start; that's
> a business only for the BIOS.
CiderPress has to be the BIOS as well as the operating system, which is
part of what makes all this so much fun. :-)
>> (Oddly enough, there is the equivalent of a "Beneath SSI RDOS".)
>> There are some bit fields in the catalog entries that I still
>> don't understand.
>
> Consult the CP/M Alteration Guide in the CP/M manual:
>
> http://www.cpm.z80.de/manuals/archive/index.htm
> http://www.cpm.z80.de/manuals/archive/cpm22htm/index.htm
This one I have seen, but I couldn't find details of filesystem structure
or directory layout in it. It has command references, boot loaders, and
what amounts to an RWTS system, but none of that helps much.
> http://home.tiscali.se/pausch/apple2/CPM.ref.txt
> http://home.tiscali.se/pausch/apple2/Apple.CPM.ref.txt
The DPB info is useful. Now, if somebody has a .NIB of a 13-sector CP/M
disk, I can try to make that work...
--
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