Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!bcstec!iftccu!bressler
From: bressler@iftccu.ca.boeing.com (Rick Bressler)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: 550Kb/sec on IDE ST1144A???
Message-ID: <7280002@iftccu.ca.boeing.com>
Date: 8 May 91 19:38:50 GMT
References: <1991May8.144034.4330@hollie.rdg.dec.com>
Organization: Boeing Commercial Airplane Group
Lines: 20

I think the primary difference is in the benchmark used.  For example, I see
almost the exact same figures, (1.2MB/sec) with CORETEST and 5-600k/s with
checkit and my AMI bios built in diagnostics.  Probably, CORETEST is not 
getting very far outside of the built in cache, or is reading without 
moving the heads at all.  It's hard to tell, since the 'real' configuration 
of the drive is hidden.  On the other hand, CORETEST reports lower rates, 
down to 900k/s on the inner tracks, and this is as it should be, since 
the density of the data drops from 44 (I think) sectors / track on the outer 
tracks, to something like 32 on inner tracks.  In fact, these numbers actually 
seem reasonable.  

Theoretically:
44 sectors / track * 3600 RPM at interleave of 1 should yield  1.28 mb / sec.
32  "          "       "                                 "      937k/sec.

These are actually about what CORETEST reports.  Perhaps it is running 
efficiently enough that it is actually getting an advantage from the 1:1 
interleave, where the other tests are real - life benchmarks where 
the 1:1 interleave is two fast.  You will note the figures are almost exactly
1/2 those of CORETEST.