From mboxrd@z Thu Jan 1 00:00:00 1970 From: hellwig.geisse@mni.thm.de (Hellwig Geisse) Date: Wed, 25 Apr 2018 08:43:05 +0200 Subject: [TUHS] Disk data layout (was: /dev/drum) In-Reply-To: <20180425013134.GM31055@eureka.lemis.com> References: <7wfu3nuqeb.fsf@junk.nocrew.org> <3A18DFEC-42B7-4234-9DD1-367733270D50@tfeb.org> <0abe01d3db28$b6573660$2305a320$@ronnatalie.com> <866bbea1-3a26-20a4-e233-1b8dc0ea2683@spamtrap.tnetconsulting.net> <20180425013134.GM31055@eureka.lemis.com> Message-ID: <1524638585.2138.26.camel@mni.thm.de> On Mi, 2018-04-25 at 11:31 +1000, Greg 'groggy' Lehey wrote: >  > But by itself that's not overly convincing.  I looked at the manual > for the IBM 3330, but I couldn't find anything specific.  Does anybody > else have any useful reference? > I kept the manual of the first hard disk drive that I ever integrated into a microcomputer system. This was a Shugart SA600 Fixed Disk Drive; the OEM manual is Copyright 1981. It had the (then) common 5.25" form factor, and could store 8 Mbytes on non-replaceable platters with 6 surfaces. Figure 2-4 in the manual shows the disk surface. "TRK 000" is the outermost track, "TRK 159" the innermost one. Even closer to the spindle is the "Head Shipping Zone" on "TRK 182", which could be accessed by a regular seek. Finally, section 4.4.1 explicitly states that the interface signal "Track 00" is true only when "the read/write heads of the selected drive are at track 00 (the outermost track)". Hellwig