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From: mangler@cit-vax.UUCP
Newsgroups: comp.periphs
Subject: Re: 5 to 20Mb/s discs for VAX under VMS - suggestions/reviews
Message-ID: <1524@cit-vax.Caltech.Edu>
Date: Sun, 18-Jan-87 20:35:01 EST
Article-I.D.: cit-vax.1524
Posted: Sun Jan 18 20:35:01 1987
Date-Received: Mon, 19-Jan-87 06:09:14 EST
References: <84@gec-rl-hrc.co.uk> <4179@utah-cs.UUCP>
Organization: California Institute of Technology
Lines: 16
Summary: memory controller bandwidth

In article <4179@utah-cs.UUCP>, cetron@utah-cs.UUCP (Edward J Cetron) writes:
>	WHY????  I recall that the max bandwith of a Qbus is about 4Mbyte/sec
> in block mode DMA, the Unibus is down around 2.2 Mbyte/sec, the massbuss was
> only about 4 Mbyte/sec, and the even the great glorious (-: BI bus is about
> 13 Mbytes/sec and none of dec's controllers are near that fast...

Unibuses and Massbuses are only half that fast.

For that matter, the VAX-750 and VAX-780 memory controllers will only do
about 5 megabytes/second, for all the busses (and the CPU) put together.

Perhaps the original poster meant mega-bits, not mega-bytes?
There are many good SMD disks with transfer rates from 8 to 20
megabits per second.

Don Speck   speck@vlsi.caltech.edu  {seismo,rutgers,ames}!cit-vax!speck