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From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Disk caching programs
Message-ID: <360@neoucom.UUCP>
Date: Wed, 14-Jan-87 11:02:27 EST
Article-I.D.: neoucom.360
Posted: Wed Jan 14 11:02:27 1987
Date-Received: Thu, 15-Jan-87 01:09:37 EST
References: <832@mprvaxa.UUCP>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 28
Summary: Lightning not too great!


I borrowed a copy of "lightning" from a friend to try out on my
AT-compatible Epson Equity III.  I set it up with a 128K buffer
size for the cache.  I found that in everyday use, the improvement
in percieved performace was minimal, if any.

For example, without lighting running, I ran DISKTIME.COM and came
up with a throughput rate of 122,000 bytes/second on the fixed
disk.  With lightning, using a 128K cache, the throughput dropped
to 92,000 bytes/second.

Thus for long xfers of data that are bigger than the area that you
reserve for the cache, you actually get a substantial decrease in
performace.

Lightning would be relatively useful for a database program that
did lots of transfers of data in and out of files that were small
enough to reside in the cache buffer.  They include a demo file
that illustrates this point nicely.  Lightning would also be a
welcome addition if you are not lucky enough to have a fixed disk
on your system, as it does improved the percieved performance on
floppies quite a bit.

Oh yes, I didn't think lightning was enough of a value to warrant
its purchase in my case, so I used Norton's wipefile to avoid being
a pirate (for any of you sensitive readers out there).

  --Bill