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Xref: sserve comp.os.os2.programmer:13318 comp.os.linux.development:122 comp.os.mach:3182 comp.os.minix:22567 comp.periphs:4140 comp.unix.bsd:12431 comp.unix.pc-clone.32bit:4087 comp.os.386bsd.development:1083 Newsgroups: comp.os.os2.programmer,comp.os.linux.development,comp.os.mach,comp.os.minix,comp.periphs,comp.unix.bsd,comp.unix.pc-clone.32bit,comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!swrinde!cs.utexas.edu!uunet!mcsun!sun4nl!relay.philips.nl!philica!adrie From: adrie@ica.philips.nl (Adrie Koolen) Subject: Re: More annoyance on the DMA problem Message-ID: <1993Aug17.070652.746@ica.philips.nl> Organization: Philips Consumer Electronics, Eindhoven, The Netherlands References: <jmonroyCBp5Ks.CM3@netcom.com> <junaid.745467838@nella30.cc.monash.edu.au> <1993Aug16.143305.16861@bilver.uucp> Date: Tue, 17 Aug 1993 07:06:52 GMT Lines: 21 In article <1993Aug16.143305.16861@bilver.uucp> bill@bilver.uucp (Bill Vermillion) writes: >In article <junaid.745467838@nella30.cc.monash.edu.au> junaid@nella30.cc.monash.edu.au (Mr A. Walker) writes: >> I always thought that 3.5 drives rotate at 250rpm= 5 rev/s. >>There are 18 sectors/track. ie 90 sectors/sec . therefore the transfer >>rate is 512*90 = 50KBytes/s (aprox.). ... > >Rev rate is 300rpm - same as MOST 5.25 drives. HD 5's can go 360, but >usually this is 'emulated' by upping the xfer rate from 250kbit/sec to >300kbit/secs. (That went back to the old 8" SD rate of 250kbit/sec at >360rpm for 1.2 megs). As far as I know, all HD 5.25" drives rotate at 360rpm (that is, the spindle). In HD mode, the bit rate is 500kbit/s, giving 15 sectors per track. To be able to read/write old 360kB diskettes, that are used by old 5.25" double density drives, rotating at 300rpm at 250kbit/s, a 5.25" HD drives uses them at 300kbit/s. (Yes, the width of the tunnel eraser on 5.25 HD drives gives also some extra problems, but that's another story.) Adrie Koolen (adrie@ica.philips.nl) Philips Consumer Electronics, Eindhoven, the Netherlands