Lisp heap vs. Mac heap

[Michael Burks <mb1i+@andrew.cmu.edu>]

A result of -108 from #_NewGWorld or #_UpdateGWorld is a long
representing all of the flags set, including gwFlagErr.  It means there
wasn't enough memory to allocate the bitmap you requested.  Oddly, if
you get -108 from #_UpdateGWorld, it is OK to call #_UpdateGWorld again
with the CGrafPtr it returned, while if you get -108 from #_NewGWorld,
calling #_UpdateGworld on the CGrafptr returned results in a Bus Error. 
I will send you some flag manipulation code I have written in a separate
message that should help.

We are all waiting for someone who knows to tell us how MCL manages its
heap(s?).  I believe that there is only one heap, since if you request a
very large chunk of memory, LISP GCs.  The only reason it would be doing
this is to try and get more space for the "real" memory you have
requested.  Also, #_maxmem consistently returns 0.  This is useless.  

SOMEONE PLEASE CLARIFY THIS - Is there a way to find out the biggest
chunk of memory I can get without crashing LISP?