Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!caen!umich!sharkey!nstar!jwt!john
From: john@jwt.UUCP (John Temples)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: IDE Transfer Rates (was: Re: TOSHIBA IDE HARDDRIVE INFO)
Keywords: HD
Message-ID: <1991Feb26.033111.7347@jwt.UUCP>
Date: 26 Feb 91 03:31:11 GMT
References: <4663@cocoa46.UUCP>
Distribution: comp
Organization: Private System -- Orlando, FL
Lines: 29

In article <4663@cocoa46.UUCP> reichert@motcid.UUCP (Chuck KD9JQ) writes:
>The current 1 to 1 interleave gives 920 - 970kbs transfer rate.

Using what -- CoreTest?  I just ran CoreTest on a Conner CP3204, and
got a very impressive 1100 kb/sec transfer rate with no software disk
caching enabled.  I suspect that this figure is almost totally
meaningless.  Since the Conner's on board cache is at least as large as
the maximum block size can CoreTest use, I think all I'm seeing is the
speed at which I can read from the drive's cache.  I doubt that
CoreTest is able to force a physical read from the drive.

After using the drive for the while, it certainly didn't feel like I
was getting the impressive performance I expected.  I ran a simple C
program I use to benchmark disk performance which writes 1024 records
of 1024 bytes each, then reads them back in sequence.  The write rate
was an appalling 70 kb/sec, with the read rate not much better at 140
kb/sec.  Results were similar under both DOS and UNIX.  Suspecting the
non-cached 20 MHz 386 wasn't fast enough to keep up with 1:1 interleave
at 12 Mbits/sec, I tried the drive on a cached 386/33, with the same
results.

Now that I find the Conner to be significantly slower than a 1:1
ST-506/MFM drive in "application level" transfer rates, I wonder if
I've set something up incorrectly, or is a 386/33 just not fast enough
to run 1:1 at 12 Mbits?  Should the drive be reformatted to 2:1, or
should I get a 486/33?  Will I get better performance from ESDI at
10-20 Mbits/sec?
-- 
John W. Temples -- john@jwt.UUCP (uunet!jwt!john)