Newsgroups: comp.sys.mac.system
Path: utzoo!utgpu!cunews!bnrgate!bigsur!news
From: webster@bnr.ca (Brent Webster)
Subject: Virtual Memory and Sys 7
Message-ID: <1991May8.143042.20137@bigsur.uucp>
Sender: news@bigsur.uucp
Organization: Bell Northern Research
Date: Wed, 8 May 91 14:30:42 GMT

Just a few comments on Apple's version of virtual memory.
I have a lowly Mac II with 8Meg of ram and a 40Meg hard-drive 
running 7.0b4 OS.  I been running a Smalltalk-80 application on
my SparcStation whose image size is about 6.5 Megs and I wanted to
try running it on my Mac (speed initially is not a concern).

I went to reconfigure my memory via the Memory control panel but it
only allowed me to increase the memory to 11 Megs. When I rebooted my
Mac, to my astonishment, my harddisk was short 11Megs and not the 
3Megs plus some overhead which I expected.  I can live with that 
but I am wishing for a more elegant solution.

Running "About this Macintosh..." indicated that the System was ONLY
taking about 1.8Meg so I figured I had 9Megs to play with.  WRONG!!!
The "Largest Unused Block:" was about 7.2 Meg and that's all the 
Smalltalk-80 application could see.

My questions are:

  Does Smalltalk-80 have to be reworked to see the other 2Meg or
  do all Mac applications only get to use the "Largest Unused
  Block:"?

  Is the "Largest Unused Block:" limited by the size of the actual
	 ram on board your Mac?

  Will I ever be able to run a 12Meg application on a Mac
  containing 8Meg of ram?

  Is Apple's version of virtual memory always going to be
  HARDDISK hungry?

  Or is this all fixed in the official "May 13" release of 
  System 7?

************************************************************
Brent Webster  (613) 763-4962 *  E-mail:
                              *   webster@bnr.ca  (NetNorth)
Bell-Northern Research Ltd    *   webster@bnr.ca.bitnet
P.O. Box 3511, Station C      *
OTTAWA, Ont, Canada           *
K1Y 4H7                       *