[comp.sys.mac.system] virtual memory arithmetic puzzle

tony@tui.marcam.dsir.govt.nz (Tony Cooper) (05/23/91)

I have a Mac II, FDHD ROMs, no floppy drives (broken), PMMU, 20MB RAM, 2
Nubus cards. Under system 7 memory control panel I do not get the 32 bit
option (the ROMs need a wash).

The Finder says I have 20MB memory of which 6MB is free. I expected this
to be 20MB with about 13MB free. Why not? Why do people with just 8MB RAM
get more virtual memory than me?

When I try to turn on virtual memory, it says 20MB memory, 8MB free disk
space - not enough disk space. Why not enough? Why does disk space have
to match RAM space? I would have expected RAM+DISK=total memory available.

If x=RAM and y=DISK then total memory available should be x+y right? Why
does y have to be >= x?

Strange stuff.

Tony Cooper
sramtrc@albert.dsir.govt.nz