Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!um-math!hyc
From: hyc@math.lsa.umich.edu (Howard Chu)
Newsgroups: comp.sys.next
Subject: Re: Next and the competition
Message-ID: <529@stag.math.lsa.umich.edu>
Date: 29 Dec 88 07:40:48 GMT
References: <2405@ncsuvx.ncsu.edu> <5725@polya.Stanford.EDU> <17911@glacier.STANFORD.EDU> <315@belltec.UUCP> <2596@udccvax1.acs.udel.EDU> <5590@cbmvax.UUCP>
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In article <5590@cbmvax.UUCP> jesup@cbmvax.UUCP (Randell Jesup) writes:
>	PClones have pretty dismal I/O rates.  On a 68000 Amiga, 7.xx MHz,
>with a SCSI controller, you can get 650K-800K _bytes_ per second through the
>file system on large reads, 1.1 MB/s using the driver directly, off good
>disks like the Quantum 80S or the CDC Wren V.

(Not to be outdone...) [sorry for this blatant me-too'ism, but...]
I get 1MB/s thru the file system on my ST, using a Quantum 80S. I suspect
a good deal of this is due to the drive's track caching, although the speed
still holds up for fragmented disk accesses. Also, the Atari ST runs the
68000 at 8.0 MHz, but the little difference can't account for all the
difference in throughput.

And, on a side note, I have to wonder about what you consider "dismal
I/O rates." PCs with ESDI drives (alright, AT clones or somesuch) get 
12 Mbit/S throughput, accessing the driver directly. That's easily in
excess of 1MB/s.

Meanwhile, since we're on this topic... What kind of "winchester" drive
is in these NeXT cubes, anyway? They seem godawful slow... (Yeah, I know
the optical disk is slow. And clunky. Gotta wonder about this thing...)
I thought this mainframe-on-a-chip channel architecture was supposed to
make I/O operations fly... Let a "find" loose on the root directory, and
watch your performance plummet. (It's pretty odd, when the only way to tell
if your machine is still running is to put your hand on the cube to feel
if the drive is spinning or not... Even the window manager stops.)
--
  /
 /_ , ,_.                      Howard Chu
/ /(_/(__                University of Michigan
    /           Computing Center          College of LS&A
   '              Unix Project          Information Systems