Path: utzoo!mnetor!uunet!dalcs!lane
From: lane@dalcs.UUCP (John Wright/Dr. Pat Lane)
Newsgroups: comp.sys.ibm.pc
Subject: Question about hard disk interleave factors
Message-ID: <2832@dalcs.UUCP>
Date: 12 Apr 88 06:08:44 GMT
Distribution: na
Organization: Math, Stats & CS, Dalhousie University, Halifax, NS, Canada
Lines: 19
Keywords: fixed disk interleave

I'm curious.  The default for interleave factor on most hard disk controllers
seems to be 3.  However, I have seen in several places where IBM and Compaq
recommend using 6 with their systems.  I have a Compaq Deskpro (8088) with a
Seagate ST225 (20 MEg) and a Western Digital W1002-WX2 (I may have the no. 
slightly wrong) disk controller.  The controller formats using 3 by default
and in fact, when I got the system the disk was apparently formatted at 3.
But the performance was lousy and so I tested every possible factor (1 to 16)
using a program which estimates the number of disk revs req. to read a track.
The optimum according to this test was 5.  I'm told that optimum interleave is
a complex combination of disk, controller, and CPU performance factors.  This
leaves me a bit dis-satisfied and I still wonder why IBM and Compaq systems 
should be different from all the rest in this respect.  Can anyone enlighten
me?  Thanks.

-- 
John Wright      //////////////////      Phone:  902-424-3805  or  902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA  B3H-4H8 
Cdn/Bitnet: lane@cs.dal.cdn    Arpa: lane%dalcs.uucp@uunet.uu.net
Uucp: lane@dalcs.uucp or {uunet,watmath,utai,garfield}!dalcs!lane