The fixed head disc used on MU5 had a 20.5ms revolution time and an inner track data rate of 2.2Mbytes/sec.
Regards Rob > -----Original Message----- > From: cctalk [mailto:[email protected]] On Behalf Of Paul > Koning via cctalk > Sent: 10 May 2018 17:30 > To: Grif <[email protected]> > Cc: General Discussion: On-Topic and Off-Topic Posts > <[email protected]> > Subject: Re: how fast were drum memories? > > > > > On May 10, 2018, at 10:37 AM, Grif <[email protected]> wrote: > > > > > > I wonder how the late generation paging disks (fixed head per track) like > DG used in the 80's compared? > > One that comes to mind is the DEC RS04. It spins at roughly 3600 rpm (a hair > less, so obviously a 2 pole induction motor running off 3-phase 60 Hz power). > Transfer rate is 0.5 megabytes per second, but still, at that RPM, average > latency is 8.5 ms. > > paul
