Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!mcsun!hp4nl!telmail!neabbs!richard
From: richard@neabbs.UUCP (RICHARD RONTELTAP)
Newsgroups: comp.unix.xenix
Subject: Re: Big Disk Advice Requested
Message-ID: <307608@neabbs.UUCP>
Date: 17 Feb 90 18:55:31 GMT
Organization: NEABBS multi-line BBS +31-20-717666 (13x), Amsterdam, Holland
Lines: 33

[ WD1007 and big disks ]
 
We recently installed an WD1007SE2 (wich means: with floppy
controller) and a Micropolis 780 MB ESDI disk. (unformatted, can't get
at de model number right now).
 
Initially the disk gave an amazing thoughput of 50 kb/sec. 
The supplier then suggested to format the disk at 53 sectors per
track, in stead of 54. That helped, the throughput is now 350 kb/sec
with the command:
dd if=bigfile of=/dev/null
 
Note that bigfile is an ordinary file, not a device. No part of the
file was in the XENIX cache, and the cache (read ahead on the WD 1007
was enabled.
 
I installed SCO's WD1007 fix (xnx133) just to be safe, but I didn't
have any problem with the drive before I installed the patch. Does
anybody know what the patch is for exactly, and which controller
revisions need it. The info with the patch says nothing, I thought I
read here it had something to do with the readahead cache on the WD.
 
Now the reason for this posting is:
 
Is 350 kb/sec an acceptable throughput? Has anyone got better? I read
the WD1007 has a full track buffer, but what track length is assumed
for that. 53 sectors (26.5 Kb) maybe is too large for the buffer. A
controller with a larger cache might do better.
 
I can't RTFM because we didn't get one with neither the disk nor the
WD1007.
 
Richard
(...!hp4nl!neabbs!richard)