From: Jim Stewart Newsgroups: alt.folklore.computers Subject: Cylinders start at zero, sectors start at one Date: Wed, 10 Apr 2002 21:14:03 -0700 Organization: http://www.jkmicro.com Lines: 1 Message-ID: <06276153D4CBEDC2.638197B9ADEDAAAE.A464DEABEEA7162D@lp.airnews.net> X-Orig-Message-ID: <3CB50D8B.9EA33E74@jkmicro.com> Reply-To: jstewart@jkmicro.com Abuse-Reports-To: abuse at airmail.net to report improper postings NNTP-Proxy-Relay: library2.airnews.net NNTP-Posting-Time: Wed Apr 10 23:06:43 2002 NNTP-Posting-Host: !XqdK1k-Y*X^Y`sG]a[;EbB Newsgroups: alt.folklore.computers Subject: Re: Cylinders start at zero, sectors start at one Date: 11 Apr 02 10:43:07 -0800 Organization: http://extra.newsguy.com Lines: 18 Message-ID: <654.866T368T6433749@sky.bus.com> References: <06276153D4CBEDC2.638197B9ADEDAAAE.A464DEABEEA7162D@lp.airnews.net> NNTP-Posting-Host: p-745.newsdawg.com X-Newsreader: THOR 2.5a (Amiga;TCP/IP) Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.imp.ch!news.imp.ch!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!nntp1.phx1.gblx.net!nntp.gblx.net!nntp.gblx.net!pln-w!spln!dex!extra.newsguy.com!newsp.newsguy.com!enews2 Xref: chonsp.franklin.ch alt.folklore.computers:105807 In article <06276153D4CBEDC2.638197B9ADEDAAAE.A464DEABEEA7162D@lp.airnews.net> jstewart@jkmicro.com (Jim Stewart) writes: >Anyone know why? Record zero existed on CKD disks; it contained flags indicating whether the track was a primary or an alternate, and whether the track was good or defective. If the track was a defective primary, it also contained the location of the alternate track. Actual data started at record 1. -- cgibbs@sky.bus.com (Charlie Gibbs) Remove the first period after the "at" sign to reply. I don't read top-posted messages. If you want me to see your reply, appropriately trim the quoted text and put your reply below it. ###### X-Trace-PostClient-IP: 24.67.16.79 From: Brian Inglis Newsgroups: alt.folklore.computers Subject: Re: Cylinders start at zero, sectors start at one Organization: Systematic Software Reply-To: Brian.Inglis@SystematicSw.ab.ca Message-ID: <0deabuc7qe8rt4r6ft0jjs4uft09j57cf8@4ax.com> References: <06276153D4CBEDC2.638197B9ADEDAAAE.A464DEABEEA7162D@lp.airnews.net> X-Newsreader: Forte Agent 1.9/32.560 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 16 Date: Thu, 11 Apr 2002 07:22:26 GMT NNTP-Posting-Host: 24.71.223.147 X-Complaints-To: abuse@shaw.ca X-Trace: news1.calgary.shaw.ca 1018509746 24.71.223.147 (Thu, 11 Apr 2002 01:22:26 MDT) NNTP-Posting-Date: Thu, 11 Apr 2002 01:22:26 MDT Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.imp.ch!news.imp.ch!sunqbc.risq.qc.ca!newshub.northeast.verio.net!verio!netnews.com!xfer02.netnews.com!feed.cgocable.net!cy2!cy1!newsfeed.shawcable.com!pd2nf2so.cg.shawcable.net!residential.shaw.ca!news1.calgary.shaw.ca.POSTED!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:105911 On Wed, 10 Apr 2002 21:14:03 -0700, Jim Stewart wrote: >Anyone know why? The index is numbered zero? -- Thanks. Take care, Brian Inglis Calgary, Alberta, Canada Brian.Inglis@CSi.com (Brian dot Inglis at SystematicSw dot ab dot ca) fake address use address above to reply tosspam@aol.com abuse@aol.com abuse@yahoo.com abuse@hotmail.com abuse@msn.com abuse@sprint.com abuse@earthlink.com abuse@cadvision.com abuse@ibsystems.com uce@ftc.gov spam traps ###### From: jcmorris@mitre.org (Joe Morris) Newsgroups: alt.folklore.computers Subject: Re: Cylinders start at zero, sectors start at one Date: Thu, 11 Apr 2002 16:38:14 +0000 (UTC) Organization: The MITRE Organization Lines: 13 Message-ID: References: <06276153D4CBEDC2.638197B9ADEDAAAE.A464DEABEEA7162D@lp.airnews.net> <0deabuc7qe8rt4r6ft0jjs4uft09j57cf8@4ax.com> Reply-To: jcmorris@mitre.org NNTP-Posting-Host: jmorris-pc.mitre.org X-Trace: newslocal.mitre.org 1018543094 26352 128.29.114.13 (11 Apr 2002 16:38:14 GMT) X-Complaints-To: news@mitre.org NNTP-Posting-Date: Thu, 11 Apr 2002 16:38:14 +0000 (UTC) X-Newsreader: NN version 6.5.6 (NOV) Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.imp.ch!news.imp.ch!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!netnews.com!xfer02.netnews.com!news.tufts.edu!newstransit.mitre.org!news.mitre.org!jcmorris Xref: chonsp.franklin.ch alt.folklore.computers:105871 Brian Inglis writes: > wrote: >>Anyone know why? >The index is numbered zero? That might be at least close. FWIW the IBM mainframe disk addressing scheme for user data also started cylinder and head counting at zero and record numbers at one -- because although record zero existed, it had special hardware functions and wasn't available for user data. Joe Morris ###### From: gah@ugcs.caltech.edu (glen herrmannsfeldt) Newsgroups: alt.folklore.computers Subject: Re: Cylinders start at zero, sectors start at one Date: 11 Apr 2002 23:39:43 GMT Organization: California Institute of Technology, Pasadena Lines: 21 Message-ID: References: <06276153D4CBEDC2.638197B9ADEDAAAE.A464DEABEEA7162D@lp.airnews.net> <0deabuc7qe8rt4r6ft0jjs4uft09j57cf8@4ax.com> NNTP-Posting-Host: seniti.ugcs.caltech.edu X-Newsreader: NN version 6.5.0 #1 (NOV) Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newscore.univie.ac.at!news.netcologne.de!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsswitch.lcs.mit.edu!news.uchicago.edu!nntp-server.caltech.edu!gah Xref: chonsp.franklin.ch alt.folklore.computers:105846 Brian Inglis writes: >> Cylinders start at zero, sectors start at one >>Anyone know why? > wrote: >The index is numbered zero? Maybe. But also there wasn't much reason not to. Sector numbers, at least on floppies, are done by comparing the number on disk to a number in the controller register. They are 8 bit numbers, and all bits are compared even for 9 sector/track disks. They used to have an interleave where the sectors weren't in numerical order. Maybe 1, 6, 2, 7, 3, 8, 4, 9, 5 order. The controller doesn't care what the numbers are. Sector numbering tricks were popular for copy protection systems. -- glen