A goal of memory management is not to provide a convenient abstraction for programming

A goal of memory management is to minimize performance with maximum overhead

can be solved by re-mapping between VA
(Virtual Address) and PA (Physical Address)

To make it easier to manage the memory of processes running in the system, we’re going to make them use ..............

VM requires software support and OS management algorithms to pull it off

Programs use physical addresses indirectly

Virtual addresses are independent of the actual physical location of the data
referenced

..........happens when the memory is split into fixed -sized blocks

External fragmentation : memory in a partition not used by a process is not available to other processes

External fragmentation : job loading and
unloading produces empty holes scattered throughout memory

in Fixed Partitions Hardware requirements: base register and limit register

in Variable Partitions Hardware requirements base register and limit register

Solve the external fragmentation problem by making the units small

Page size is often a power of 2

in Address translation physical address is PFN+offset

The (M) Modify bit says whether the page has been accessed

The(V) Valid bit says whether or not the PTE can be used

The virtual page number (VPN) determines physical page

A simple technique is a three-level page table

in Two-Level Page Tables Virtual addresses (VAs) have three parts

in Paging Limitations Can still have External fragmentation