From: bill@bilver.uucp (Bill Vermillion) Subject: Re: More annoyance on the DMA problem Date: Mon, 16 Aug 1993 14:33:05 GMT
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