Subject: Re: .dsk file format Path: lobby!newstf02.news.aol.com!portc01.blue.aol.com!portc03.blue.aol.com!newsfeed.mathworks.com!cyclone.swbell.net!nnrp3.sbc.net.POSTED!not-for-mail Message-ID: <39A19318.DD0FAAD8@swbell.net> From: Rubywand X-Mailer: Mozilla 4.72 [en] (Win95; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.emulators.apple2,comp.sys.apple2 References: <399ef59b$0$9446@senator-bedfellow.mit.edu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 29 Date: Mon, 21 Aug 2000 15:37:44 -0500 NNTP-Posting-Host: 207.193.227.153 X-Complaints-To: abuseswbell.net X-Trace: nnrp3.sbc.net 966890217 207.193.227.153 (Mon, 21 Aug 2000 15:36:57 CDT) NNTP-Posting-Date: Mon, 21 Aug 2000 15:36:57 CDT Organization: SBC Internet Services Xref: lobby comp.emulators.apple2:20887 comp.sys.apple2:105023 Benjamin Fry writes ... > > hi all, > > i'm curious to find out more about byte-level (or i guess nybble, in this > case) format used for apple II discs. essentially, if i'm looking for the > doc that would allow me to write a util that can CAT a .dsk image, or pull > individual files from the .dsk. could someone point me in the correct > direction on where i might find such a thing? > .... The format of a standard 5.25" .dsk disk image file is pretty simple. It includes only the data from a standard 35-track, 16-sector disk. It does not include any Address Header, etc. info which is embedded in a diskette as part of the formatting process. Usually, data in a .dsk file will be in the same order as used by DOS 3.3. So, for example, the first 256-byte block of bytes in a .dsk file will correspond to Track 0/Sector 0. The 16th 256-byte block will correspond to Track 0/Sector 15 (or, in hex notation: Track $00/Sector $0F). The 17th 256-byte block will correspond to Track 1/Sector 0, ... etc.. Besides the book mentioned by Matthew, you can find some DOS 3.3 info in the Csa2 Apple II FAQs at http://home.swbell.net/rubywand/Csa2DOSMM.html . Rubywand