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From: gillies@m.cs.uiuc.edu (Don Gillies)
Subject: Re: System 7.0 and RAM
Message-ID: <1991Apr11.220129.1591@m.cs.uiuc.edu>
Organization: University of Illinois, Dept. of Comp. Sci., Urbana, IL
References: <1991Apr8.010338.14202@murdoch.acc.Virginia.EDU> <1991Apr9.220140.18228@murdoch.acc.Virginia.EDU> <1991Apr11.181853.9845@Think.COM>
Distribution: usa
Date: Thu, 11 Apr 91 22:01:29 GMT
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In my limited experience on a Xerox 8010, I concluded that virtual
memory would give you about twice as much "usable" memory as physical
memory.  So if you have 5Mb of DRAM, 10Mb of virtual memory is a
reasonable limit.  With 2Mb of DRAM, 4Mb was a reasonable limit for
virtual memory.

Beyond that limit, even if the code has been repackaged to minimize
working sets (i.e. to minimize paging), the machine would still start
to thrash badly.  I suspect the Mac OS is very poorly structured for
virtual memory, so your mileage may vary.


Don Gillies	     |  University of Illinois at Urbana-Champaign
gillies@cs.uiuc.edu  |  Digital Computer Lab, 1304 W. Springfield, Urbana IL
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"WAR!  UGH! ... What is it GOOD FOR?  ABSOLUTELY NOTHING!"  
	- the song "WAR" by Edwin Starr, circa 1971

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