Newsgroups: comp.sys.mac.system
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!mdisea!jackb
From: jackb@MDI.COM (Jack Brindle)
Subject: Re: No cmd-opt-e in system 7?? (answer)
Message-ID: <1991Jun21.171557.25085@MDI.COM>
Sender: news@MDI.COM
Organization: Motorola, Mobile Data Division - Seattle, WA
References: <1991Jun20.232314.4961@m.cs.uiuc.edu>
Date: Fri, 21 Jun 1991 17:15:57 GMT
Lines: 36

In article <1991Jun20.232314.4961@m.cs.uiuc.edu> gillies@m.cs.uiuc.edu (Don Gillies) writes:
>There is one irritating thing about the new DA scheme in system 7.0.
>You can no longer open a DA within the application heap.  Frequently,
>I run my FOP postscript interpreter, which requires me to operate the
>of my memory.
>
>It is very irritating to be unable to open the chooser because you're
>low on memory.  Sometimes you get to a critical section in your work
>and you want to print.  Leaving your application might destroy the
>object you want to print.  The chooser has no memory so you end up
>deadlocked, unable to choose -- unable to print.  This was never a
>problem before. Some life-critical DAs should be able to run in the
>system heap, using some sort of memory emergency-reservation scheme.

How would this help? The Mac would try to load the chooser into the
system heap, discover it needs more room, try to expand it, only to find
there wasn't enough memory, then give you an "out of memory" dialog.
You would be left in the exact same situation you are in now. At least
you have a chance of running the DA if you have VM going (if you can
run it...). As I understand it, the system heap never gets swapped,
so it still would have memory problems after loading the DA into the
system.

This brings up another question. Is it possible to lock out a running
application that has been swapped out? Consider this scenerio: Some
piece of  code is loaded into the system heap. It causes a large
application to be swapped. The new code is locked, and increases the
system heap so that the application no longer has enough memory available
to run. Possible? Or will the system catch it and keep the additional
code from loading into the system?

Hmmmmm.......

Jack B,
ham radio: wa4fib/7

