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US Patent 5063499
Though this might interest some people....it's basically how virtual memory was first implemented on the early macs.
US Patent 5063499
US Patent 5063499
Interesting. Yes, the original Macs had everything executing as supervisor. When they wanted to use virtual memory they realised they had shot themselves in the foot.
The original Mac's virtual memory is like Windows 3 virtual memory, it just expands the memory available to the processor but each process gets a different section of this memory.
So even though you have virtual memory, you still have to configure each application's heap size.
This is unlike UNIX or Windows NT, where each process gets it's own totally isolated view of memory as if it owned the whole address space.
A good test of the difference is "can the operating system implement fork()?".
The original Mac's virtual memory is like Windows 3 virtual memory, it just expands the memory available to the processor but each process gets a different section of this memory.
So even though you have virtual memory, you still have to configure each application's heap size.
This is unlike UNIX or Windows NT, where each process gets it's own totally isolated view of memory as if it owned the whole address space.
A good test of the difference is "can the operating system implement fork()?".