Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!keith
From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.mac.system
Subject: Re: Some System 7 questions...
Message-ID: <53540@apple.Apple.COM>
Date: 31 May 91 18:20:19 GMT
References: <1991May31.151901.10137@Think.COM> <1991May31.155150.5074@hubcap.clemson.edu> <13787@goofy.Apple.COM>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 25

In article <13787@goofy.Apple.COM> lsr@Apple.COM (Larry Rosenstein) writes:
>In article <1991May31.155150.5074@hubcap.clemson.edu> jcocon@hubcap.clemson.edu (james c oconnor) writes:
>>[much deleted]
>>
>>Did Apple change the caching algorithm?  If not, why the huge cache?
>>I'd heard that the cache was pretty much a waste of RAM if it got over
>>some small number, say 128k (remember when that was how much RAM Macs
>
>I think System 7 does fix the caching algorithm.  At least if you click the
>Use Defaults button the system often recommends larger caches (e.g., 512K on
>my 16Mb fx).

Under system 6.0.x, when a file is closed, the cached blocks associated
with that file are places on a free chain. This means that if files
are opened and closed a lot (like MPW's header/interface files), they
gain little benefit from the cache. Under System 7.0, when a file is
re-opened, any cached blocks belonging to it are reclaimed from the
free chain.

-- 
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Keith Rollin  ---  Apple Computer, Inc. 
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"But where the senses fail us, reason must step in."  - Galileo