[ILUG] thoughts on malloc... Memory Pools ?

[David Golden]

On Wednesday 27 March 2002 10:45, John P. Looney wrote:
> On Wed, Mar 27, 2002 at 12:03:20AM +0000, David Golden mentioned:
> > Sounds in some ways a little bit like AmigaOS 3.x memory pooling
>
>  I was thinking that, but didn't have the balls to post.
>
>  Someone was bound to say "So, they had memory pooling & virtual memory,
> but not memory protection ?".
>

:-)

Actually, come to think of it, a major carrot CBM was using at the time 
(1992-3 ???) to persuade people to use AllocPooled() instead of AllocMem() 
was that applications which used AllocPooled() would be ready for when
they eventually introduced memory protection and non- kludgy-addon virtual 
memory.

Basically, their intent was to protect each pool from the others, with old 
applications consigned to their shared hell (the old global memory pool), a 
bit like 16-bit applications on some versions of windows.   New applications 
would have their own per-thread private pools, and no longer be able to cause 
system-wide "Sanity check on memory list failed" crashes, legacy applications
would still have been able to bring down the system.

ISTR there were pretty difficult technical hurdles they ran in to with the 
above plan (every structure in AmigaOS eventually points to something else
somewhere, the whole house of cards is built around linked lists and uses 
message-passing-by-reference extensively), and then CBM died, so it never 
happened, and the Amiga memory subsystem stagnated until very recently. -  
Thomas Richter's mmu.library, which has a stab at memory-protection
functionality, has gained wide support among the few remaining Amiga 
application writers.