MEMORY MANAGEMENT

Background

Address binding of instructions and data to memory addresses can happen at three stages:

Logical versus Physical Address Space

Memory-management unit (MMU) - hardware device that maps virtual to physical address.

Swapping

Contiguous Allocation

Paging - logical address space of a process can be noncontiguous; process is allocated physical memory wherever the latter is available.

Implementation of page table

Multilevel Paging - partitioning the page table allows the operating system to leave partitions unused until a process needs them.

Inverted Page Table

One entry for each real page of memory; entry consists of the virtual address of the page stored in that real memory location, with information about the process that owns that page.

Shared pages

Segmentation - memory-management scheme that supports user view of memory.

Sharing

Protection

With each entry in segment table associate:

Allocation

Segmentation with Paging

Considerations in comparing memory-management strategies: