Disjoint memory schemes

This is similar to fixed partitions in a sense that there are discrete sizes (page frame sizes).

However, not all of a process memory has to be contained in one. Instead, memory is “virtually contiguous”, using “logical memory”. Under the hood, this gets mapped to “page frames”, which reside on physical memory.

How is mapping done?

disjoint memory mapping

Mapping is done with page tables and translation look-aside buffers (TLBs).

How do we protect memory access between processes?

A natural question is how we can ensure that a process does not accidentally overwrite a physical memory address which is in use.

page scheme: protection

Can we further optimize disjoint memory allocation ?

A processes’ memory consumption is large. Context switching between processes will be costly.

We make the observation that a processes’ memory consumption can be segmented: text, data, heap, stack.