Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!hsdndev!burrhus!isr.harvard.edu!kik
From: kik@isr.harvard.edu (Ken Kreshtool)
Newsgroups: comp.sys.mac.system
Subject: Answer: why 350k RAM "missing" on IIsi
Summary: built-in video memory not reported in "About This Mac..."
Message-ID: <1991Jun29.180600.8449@burrhus.harvard.edu>
Date: 29 Jun 91 18:06:00 GMT
Sender: news@burrhus.harvard.edu (USENET News System)
Organization: Harvard University, Cambridge, MA
Lines: 13
Originator: kik@isr.harvard.edu

Thanks to all those who answered.  I had noticed that the sum of allocated
and unused memory always seemed to add up to about 350k less than the 
total memory when I checked in the "About This Macintosh..." thing, even
System 7.  Several people suggested that it might be the RAM reserved for
running the built-in video.  They are right, as I discovered by changing
the reserved memory in the Monitors extension.  2-bit video reserves about
90k, to which ya gotta add just what you'd expect for other settings:
another 32k for 4-color, or 96k for 16-color, or 256k for 256-color.

Still, it seems the System should be smart enough to report this in the
the "About This Mac..." box...

Ken Kreshtool (kik@wjh12.harvard.edu)