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From: shatara@memit.dec.com (Chris Shatara)
Newsgroups: comp.sys.apple
Subject: Re: SCSI TIMER & V5.0
Message-ID: <707@mountn.dec.com>
Date: 27 Aug 89 13:45:59 GMT
Sender: news@mountn.dec.com
Organization: Digital Equipment Corporation
Lines: 34

# 
## I have already optimized the interleave under V4.0 with a 40% improvement 
## in read times and was wondering if the interleave should change because 
## of the SCSI driver improvements in System 5.0
# 
#When you reran these and got a 40% improvement was it because you changed
#the interleaf?  (Or maybe it was because of the driver/ADU improvements in
#V4.0?)  (I really am asking.  I'm not trying to put words in your mouth.  I
#would like to know since I formatted my drive under version three.)
# 

The improvement was from the interleave. The reason I say this Is that I 
ran the disk for a month under V4.0 BEFORE I got a copy of SCSI hacker and 
Timer.  I never ran the hard disk under System software V3.2.

I just finish this procedure again with new system disk.  As before I ran 
a while with the old interleave settings and by changing them was able to 
reduce the read times by another 15% (according to SCSI timer). 

Interesting enough the docs which came with SS 5.0 suggested 1:1 or 1:2 as 
an interleave setting (infact the software would use one of these settings 
if you allowed it to do the low level format)  I ended up with a setting 
of 5.  (4 gave me the lowest setting and 5 gave me some margine for 
tolerances).  I am running with an Apple SCSI board and a SEAGATE st138N 
drive.

/chris

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|        Chris Shatara       |      Internet:    shatara@memit.dec.com      |
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