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From: morris@dms.UUCP (Jim Morris)
Newsgroups: comp.windows.ms,comp.sys.ibm.pc.misc
Subject: Re: Hyperdisk -- the Smartdrive replacement
Message-ID: <1119@dms.UUCP>
Date: 1 Aug 90 18:30:02 GMT
References: <1990Jul31.133423.19743@watserv1.waterloo.edu>
Organization: Atari Games Inc., Milpitas, CA
Lines: 35

From article <1990Jul31.133423.19743@watserv1.waterloo.edu>, by tom@mims-iris.waterloo.edu (Tom Haapanen):
> 
> Well, to me it lloks like Hyperdisk is slower than SamrtDrive unless you
> enable write caching, and it takes another 7K of DOS memory, too --- which

Hyperdisk will load itself into Shadow-Ram on some 386 systems, especially
if you run qemm or 386^max, this saves your valuable lo memory.


> Personally I wouldn't take a chance by caching writes; a power failure or
> a system crash might wipe out what you thought had already been written
> to disk.
> 
A power failure will probably wipe out your disk anyway, an extra 500ms wait
before the data writes out is unlikely to increase the risk by much. Unix
systems all do write-back caching, I usually put them on UPS's if I am really
paranoid, but my system at home is not on a UPS, and I have not had a problem
yet!!. Of course according to Murphy, the power-out will hit before you
have even saved the 2 hour editing session!! (I like to use editors with timed
back-up, just to annoy Murphy).


> If you want higher disk performance, consider a disk controller with a
> built-in cache.
>
Actually I believe you will find that a disk cache running on a 386 in 32-bit
memory will outperform a H/W disk cache. The memory read and write to a disk
cache on a pc bus is subject to the 16 bit 8Mhz bus speed, whereas a disk
cache stored in 32-bit memory has much faster access time. Of course using
both (If you have the money!!) would be the best solution.
-- 
Jim Morris.         {motcsd|weitek}!dms!morris or morris@dms.UUCP 
Voice	(408) 434-3798
Atari Games Corporation, 675 Sycamore Drive, Milpitas CA 95035 USA
(Arcade Video Game Manufacturer, NOT Atari Corp. ST manufacturer).