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From: logic@wet.UUCP (Henry Kwan)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Quantum HD's
Message-ID: <931@wet.UUCP>
Date: 22 Jan 90 09:19:54 GMT
References: <1030@ux.acs.umn.edu> <19640008@hpvcfs1.HP.COM>
Reply-To: logic@wet.UUCP (Henry Kwan)
Organization: Wetware Diversions, San Francisco
Lines: 28

In article <19640008@hpvcfs1.HP.COM> stevem@hpvcfs1.HP.COM (Steve Miller) writes:
>
>Also remember that the Quantum has a raw access time of about 19ms and the 12ms
>number is based on the performance of the drives 64Kbyte cache.  The degree
>to which this cache helps is dependent on how the drive is used, it's
>possible that the cache doesn't help at all for the "SCSI Evaluator" because
>of the way the evaluator does it's testing.
>
>
>Steve

According to official Quantum literature, the average seek time for a
ProDrive is 19 ms.  The oft-quoted time of 12 ms comes from the 11.7 ms seek
time that Quantum says their drives gets from a mixture of 50% random and
50% sequential seeks.

The 64K DisCache in the ProDrives is a lot more advanced than most of the
other drive caches out there.  You have a lot of control over it.  It could
be all configured for track buffering or pre-fetching or whatever.

The new Quantums will have even better firmware to include thing like zero
latency reads as well as command queuing.  Very nice.
 
-- 
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