Return to BSD News archive
Xref: sserve comp.os.os2.programmer:13315 comp.os.linux:53186 comp.os.mach:3177 comp.os.minix:22563 comp.periphs:4132 comp.unix.bsd:12426 comp.unix.pc-clone.32bit:4075 comp.os.386bsd.development:1076 Newsgroups: comp.os.os2.programmer,comp.os.linux,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!constellation!osuunx.ucc.okstate.edu!moe.ksu.ksu.edu!vixen.cso.uiuc.edu!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!tarpit!bilver!bill From: bill@bilver.uucp (Bill Vermillion) Subject: Re: More annoyance on the DMA problem Organization: W. J. Vermillion - Orlando / Winter Park, FL Date: Mon, 16 Aug 1993 14:33:05 GMT Message-ID: <1993Aug16.143305.16861@bilver.uucp> References: <jmonroyCBoq14.Kz0@netcom.com> <jmonroyCBp5Ks.CM3@netcom.com> <junaid.745467838@nella30.cc.monash.edu.au> Lines: 21 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). The 3.5" data rate is 500kbit/sec for HD. Remember that there are a lot of bytes used up by track and sector numbering and a few bytes for pad at the end of the track to make up for differing rotational speeds. No need to try to work backward. These are standard hardware specs. -- Bill Vermillion - bill@bilver.uucp OR bill@bilver.oau.org