Based on MichaelGoren’s answer in the following question, I understood that the shared memory is mapped into the Memory Mapping Segment, the space between the Heap and Stack segments in the process address space.

Shared memory in process address space?

I’m curious why this space is used for shared memory?

I kinda thought the two processes involved would find a third, irrelevant memory space. So how do they decide which process’s MMS to use?

Thanks