Partitioning An early method of managing memory Pre-virtual memory Not used much now But, it will clarify the later discussion of virtual memory if we look first at partitioning Virtual Memory has evolved from the partitioning methods
11 Partitioning • An early method of managing memory – Pre-virtual memory – Not used much now • But, it will clarify the later discussion of virtual memory if we look first at partitioning – Virtual Memory has evolved from the partitioning methods
Types of Partitioning FiXed Partitioning Dynamic Partitioning Simple Paging Simple Segmentation Ⅵ rtual Memory Paging Virtual Memory Segmentation 12
12 Types of Partitioning • Fixed Partitioning • Dynamic Partitioning • Simple Paging • Simple Segmentation • Virtual Memory Paging • Virtual Memory Segmentation
Fixed Partitioning Equal-size partitions ( see fig 7. 3a) Any process whose size is less than or equal to the partition size can be loaded into an available partition oS can swap a process out of a partition If none are in a ready or running state a) Equal-size partitions 13
13 Fixed Partitioning • Equal-size partitions (see fig 7.3a) – Any process whose size is less than or equal to the partition size can be loaded into an available partition • OS can swap a process out of a partition – If none are in a ready or running state
Fixed partitioning problems A program may be too big to fit into a partition Main memory use is inefficient Any program, no matter how small, occupies an entire partition This is results in internal fragmentation 14
14 Fixed Partitioning Problems • A program may be too big to fit into a partition • Main memory use is inefficient. – Any program, no matter how small, occupies an entire partition. – This is results in internal fragmentation