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From: elg@killer.Dallas.TX.US (Eric Green)
Newsgroups: comp.sys.amiga
Subject: DiskPerf results
Message-ID: <7965@killer.Dallas.TX.US>
Date: 30 Apr 89 17:11:18 GMT
References: <21149@srcsip.UUCP>
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In message <21149@srcsip.UUCP>, carpent@coltrane.SRC.Honeywell.COM (Todd Carpenter) says:
>In case you folks are interested, I ran DiskPerf on my beastie:
>A2090a
>A2620
>Rodime SCSI HD.  Basically, it is their 180MB 5 1/4" SCSI drive, with a few
>       hand modifications.  Like, 12msec access, 12MHz transfer.  Hee-hee.
>r/w speed:	    buf 32768 bytes, rd 635500 byte/sec, wr 372275 byte/sec
>r/w speed:	    buf 131072 bytes, rd 655360 byte/sec, wr 427990 byte/sec
>r/w speed:	    buf 524288 bytes, rd 699050 byte/sec, wr 455902 byte/sec
>Unfortunately, I was surprised the numbers were so low.  I had hoped for
>significantly higher. Anyone have any suggestions?  Or are these fast for Amiga
>drives?


I suspect that the limiting factors are a) the file system, and b) the
A2090A. I got about the same results from a 2090A and a Quantum 80S.
The 2090A limits speed because it is limited to the old 1mb/sec
asynchronous SCSI protocol (meaning that however hot your drive is,
it's limited to 1mb/sec max throughput). However, someone else got
basically the same numbers from a Quantum 80s and a Microbotics
Hardframe (which has the new 5mb/sec synchronous SCSI, i.e., will take
data as fast as the Quantum can dish it out, 4mb/sec). So I have to
conclude that file system overhead has something to do with it,
too....

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