Path: news1.icaen!news.uiowa.edu!news.physics.uiowa.edu!math.ohio-state.edu!howland.erols.net!sunqbc.risq.qc.ca!news.uow.edu.au!david From: david@uow.edu.au (David Wilson) Newsgroups: comp.sys.apple2,comp.sys.apple2.programmer Subject: Re: Disk format Date: 10 Feb 99 23:14:09 GMT Organization: University of Wollongong, Australia Lines: 25 Message-ID: References: <79sue8$ad6$1@platane.wanadoo.fr> NNTP-Posting-Host: wraith.cs.uow.edu.au X-Trace: wyrm.its.uow.edu.au 918688472 11911 130.130.64.1 (10 Feb 1999 23:14:32 GMT) X-Complaints-To: usenet@wyrm.its.uow.edu.au NNTP-Posting-Date: 10 Feb 1999 23:14:32 GMT X-Newsreader: NN version 6.5.0 #15 (NOV) Xref: news1.icaen comp.sys.apple2:144981 comp.sys.apple2.programmer:10422 "Aurelien Mere" writes: >Does anybody know the disk format of 3"5 apple II disks ? >I mean : number of sectors, tracks, bytes/sectors, heads, etc... It is the same (well almost) as the Mac: 80 tracks 2 heads 512 bytes/sector (Mac has extra 12 bytes for flags, Apple // has zeros) Variable number of sectors per track For a single sided disk: Tracks Sectors/Track Sector #s 0-15 12 0-191 16-31 11 192-367 32-47 10 368-527 48-63 9 528-671 64-79 8 672-799 I assume that for a double sided disk you just double the sector numbers. See Inside Macintosh Volume II, chapter 7. -- David Wilson School of IT & CS, Uni of Wollongong, Australia david@uow.edu.au Path: news1.icaen!news.uiowa.edu!uunet!ffx.uu.net!in5.uu.net!newsfeed.wli.net!newsfeed.berkeley.edu!cyclone.swbell.net!typhoon01.swbell.net.POSTED!not-for-mail Message-ID: <36C235CB.71C9538B@swbell.net> From: Rubywand Reply-To: rubywand@swbell.net X-Mailer: Mozilla 4.5 [en] (Win95; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.sys.apple2,comp.sys.apple2.programmer Subject: Re: Disk format References: <79sue8$ad6$1@platane.wanadoo.fr> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 44 Date: Wed, 10 Feb 1999 19:43:39 -0600 NNTP-Posting-Host: 207.193.12.56 X-Complaints-To: abuse@swbell.net X-Trace: typhoon01.swbell.net 918697403 207.193.12.56 (Wed, 10 Feb 1999 17:43:23 PDT) NNTP-Posting-Date: Wed, 10 Feb 1999 17:43:23 PDT Organization: SBC Internet Services Xref: news1.icaen comp.sys.apple2:145015 comp.sys.apple2.programmer:10427 David Wilson writes ... > > "Aurelien Mere" writes: > >Does anybody know the disk format of 3"5 apple II disks ? > >I mean : number of sectors, tracks, bytes/sectors, heads, etc... > > It is the same (well almost) as the Mac: > > 80 tracks > 2 heads > 512 bytes/sector (Mac has extra 12 bytes for flags, Apple // has zeros) > Variable number of sectors per track > > For a single sided disk: > > Tracks Sectors/Track Sector #s > 0-15 12 0-191 > 16-31 11 192-367 > 32-47 10 368-527 > 48-63 9 528-671 > 64-79 8 672-799 > > I assume that for a double sided disk you just double the sector numbers. > Yes. For 2 sides, a 512-byte sector is usually called a "block" and the numbering of blocks alternates between the sides for each Track. For example ... Track 0, Side 1 has blocks 0-11 (decimal) Track 0, Side 2 has blocks 12-23 (decimal) So, you end up with ... Tracks Blocks/Track Block Numbers 0-15 12/side= 24 0-383 (decimal) ... 64-79 8/side= 16 1344-1599 (decimal) Rubywand