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From: ralf@b.gp.cs.cmu.edu (Ralf Brown)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Mylex vs. Micronics vs. AMI 386 motherboards
Message-ID: <6298@pt.cs.cmu.edu>
Date: 26 Sep 89 23:44:47 GMT
References: <1235@mitisft.Convergent.COM> <22538@cup.portal.com>
Organization: Carnegie-Mellon University, CS/RI
Lines: 19

In article <22538@cup.portal.com> cliffhanger@cup.portal.com (Cliff C Heyer) writes:
}there is supposed to be making a board
}with SCSI directly connected to the
}CPU bypassing the AT bus...so you can
}get "real" I/O up to 900KB/sec rather
}than 250KB/sec like all the other

Except that the AT bus is not a bottleneck until you get way beyond current
disks and controllers.  Running at the equivalent of 8 MHz/1 ws with a 16-bit
controller, you can pump 5.3 megabytes per second across the bus.... (3 clocks
for every 2 bytes, at 125 ns per clock cycle).  HD controllers with hardware
caches regularly get data transfer rates of over 3 megs per second (and that
includes BIOS and other overhead at least once for every 64K transferred).

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