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From: philip@pescadero.Stanford.EDU (Philip Machanick)
Newsgroups: comp.lang.postscript
Subject: Disk cache? [was Re: Obscure LaserWriter features}
Message-ID: <1990Sep5.211829.4130@Neon.Stanford.EDU>
Date: 5 Sep 90 21:18:29 GMT
References: <1546@chinacat.Unicom.COM> <428@macuni.mqcc.mq.oz> <1510@chinacat.Unicom.COM> <1899@mountn.dec.com>
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Reply-To: philip@pescadero.stanford.edu
Organization: Computer Science Department, Stanford University
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In article <1546@chinacat.Unicom.COM>, woody@chinacat.Unicom.COM (Woody
Baker @ Eagle Signal) writes:
> It would not be a matter of economy, but rather one of speed.  Being able
> to write to the disk at the full SCSI speed would ridiculously speed printing
> up, as you can use the disk as a *VERY* large print buffer...

It would be interesting to test this statement. In general, caching works by
having a relatively small amount of fast memory, rather than a relatively
large amount of slow memory. For the price of an external 20M SCSI disk, you
could probably buy about 4M of RAM. I would guess in most practical
applications, increasing the amount of RAM sould be a more effective
way of speeding things up (RAM access time: about 100ns; disk access time:
around 20ms - 200 times slower, if my arithmetic is right; not the whole
story, but the right order of magnitude...).

Philip Machanick
philip@pescadero.stanford.edu