Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!njin!princeton!phoenix!mbkennel
From: mbkennel@phoenix.Princeton.EDU (Matthew B. Kennel)
Newsgroups: comp.windows.x
Subject: Re: Contents of windows
Message-ID: <8079@phoenix.Princeton.EDU>
Date: 2 May 89 06:46:08 GMT
References: <4009@ficc.uu.net> <8904281155.AA02450@expire.lcs.mit.edu> <723@boing.UUCP>
Reply-To: mbkennel@phoenix.Princeton.EDU (Matthew B. Kennel)
Distribution: na
Organization: Princeton University, NJ
Lines: 26

In article <723@boing.UUCP> dale@boing.UUCP (Dale Luck) writes:
>   The technology used by the layer library in the Amiga window system is
>setjmp/longjmp based. When operations occur that may require more memory to be
>consumed, they are done in a very careful order. For instance we allocate the
>new set of structures and associated bitmaps before freeing the original ones, etc.
>This allows the Amiga to back out of a partially completed operation and restore
>the state of the machine before the operation took place if a memory allocation
>fails.
>

Correct me if I'm wrong, but I have heard that the Amiga only allocates
nonrelocatable blocks of memory.  Without the use of hardware memory
mapping (does it do that?) I would guess that frequent changes of the
windows combined with many allocates/deallocates would result in memory
fragmentation that would cause memory requests to fail (needed for
backing store etc.) even when there is enough actual memory left.  (But not
contiguously)  It's really hard to believe that 512k would hold up long
for server, clients, and display in this situtation.

>-- 
>Dale Luck     GfxBase/Boing, Inc.
>{uunet!cbmvax|pyramid}!amiga!boing!dale


Matt Kennel
mbkennel@phoenix.princeton.edu