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DOS had a similar mechanism to "zones" with its "arenas", but it didn't
bother with handles (since segments were such a spiffy mechanism - 
*irony*).

Windows 3.1 defined a "local heap" that was reclaimed when a program
exited, and used handles when handing out memory.  However, Windows 3.1
actually used virtual memory to deal with the local heap and program
machine code, so it was actually slightly more robust than the Mac.

The problem was that all three of these operating systems _also_ allowed
the allocation of memory outside the application-specific pools... so a
program could allocate memory outside its own zone/arena/heap and fail to
return it before exiting.  This was particularly a problem for Win3.1
because after the introduction of "386 enhanced mode" and typical memory
requirements exceeded 4MB most programmers allocated all memory from the
global heap and immediately locked every handle they received because the
local heap was still only 64K!

So I think every operating system has recognized the need to reclaim
memory when a program exits, but without (and sometimes with) memory
management hardware support programming mistakes could still cause
"global" memory leaks in the instances I am familiar with.  So I have no
examples to fit Pete's original question, but the problem was quite real
anyway.

---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil@dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...2k
---------------------------------------------------------------------------

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