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From: wlsmith@valve.heart.rri.uwo.ca (Wayne L. Smith)
Newsgroups: comp.periphs.scsi,comp.sys.ibm.pc.hardware
Subject: Re: How much faster is a 16 bit SCSI Card than the ST02?
Message-ID: <3167@ria.ccs.uwo.ca>
Date: 29 May 91 16:40:37 GMT
References: <396@oiscola.Columbia.NCR.COM>
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Followup-To: comp.periphs.scsi
Organization: The John P. Robarts Research Institute, London, Ontario
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In article <396@oiscola.Columbia.NCR.COM> dmoyer@oiscola.Columbia.NCR.COM (Dan Moyer) writes:
>
> 
>220-300 K bytes/sec transfer time, and a 28-31 ms access time.
>These figures seem reasonable for a 8-bit, dumb scsi board and
>this disk..
> 
>I am considering purchase of a 16 bit board.
> 
>I currently operate DOS and sometimes Windows 3.0 now.   Sometime
>in the future (6-12 months), I'd like to be able to use OS/2 2.0 or
>Unix.  
> 
I have had the same combo in my 286 (296N/ST02 controller)
I have low-level formatted the drive using the ST02 bios, using 1:1, 2:1, and
3:1 interleaves.  The one that worked best was 2:1.
At 2:1, both Spinrite and Core gave 425 +/- 25 KB/sec transfer rate.
The 1:1 gave less than 100 k/sec, and 3:1 was less than 2:1 (I forget what
it actually was).  I once heard that it was a fundamental problem with the
drive electronics that prevented good performance when formatted @ 1:1, but
I have talked to seagate and they say that it is the ST02 controller which
is limiting.  They say that the drive will do over 1M/sec with a 16 bit
controller.  I would say that, at least in a 286 system, the benefit/cost
in going to a 16 bit controller is nil.  When I tested the 296 head to head
with a ST251-1 (1:1 interleave, MFM) in the same system (using QAplus), 
both had identical transfer rates.  So, if you're satisfied with 17 sectors/
track 1:1 interleaved MFM, you'd be satisfied with 30 odd sectors/track
RLL at 2:1 interleave.

Someone else will have to tell you what to expect with a 16 bit SCSI
card, but I hear that Adaptec is best.