[comp.sys.mac.system] System 7.0 and Virtual memory

tcwan@umiami.ir.miami.edu (04/12/91)

Thanks to those folks who responded to my questions about System 7.0
and Virtual Memory. Someone mentioned the possibility of Interrupt tasks
causing page faults within another page fault when VM is running and the
code resources were not locked in physical memory, and I'm
just wondering if there's any consistent way to determine whether an
Application or INIT or whatever is liable to do such a thing.

This is especially true for pd/shareware stuff that is obtained from
the various archives. Imagine the trouble involved in tracking down
what the culprit is (VM, the INIT/application, or combination thereof).

While we are at it, could someone explain a little of how VM in System 7.0
is implemented, and how it deals with exceptions (page faults, etc)?
Is is page oriented or segment oriented?
I have taken an OS class where we dealt with VM in a simple paging scheme,
but not at the level of complexity that a real OS requires :)

So the question is, are we gaining a new functionality at the expense
of much greater complexity and possibly greater risk of system bombs?

Again, thanks to anyone who could provide some answers and I'm sure
the rest of us (in the net) will be very grateful. :)

tcwan@umiami.miami.edu
Grad. student in Computer Engineering
University of Miami, FL