Memory Management Techniques(p292) Fixed Partitioning(固定分区) ynamic Partitioning(动态分区 Simple paging(简单分页 Simple segmentation(简单分段) Ⅴ irtual- Memory Paging(虚拟分页 Ⅴ irtual- Memory Segmentation(虚拟分段) MEMORY MANAGEMENT
MEMORY MANAGEMENT Memory Management Techniques（p292） • Fixed Partitioning(固定分区) • Dynamic Partitioning（动态分区） • Simple Paging（简单分页） • Simple Segmentation（简单分段） • Virtual-Memory Paging（虚拟分页） • Virtual-Memory Segmentation（虚拟分段）
3.2 Memory Partitioning(p292) Fixed Partitioning Dynamic Partitioning Buddy system伙伴系统) MEMORY MANAGEMENT
MEMORY MANAGEMENT 3.2 Memory Partitioning(p292) • Fixed Partitioning • Dynamic Partitioning • Buddy System(伙伴系统)
Fixed Partitioning(p294) Main memory is divided into a number of static partitions at system generation(装入)time.A process may be loaded into a partition of equal or greater size The partitions can be equal size or not. MEMORY MANAGEMENT
MEMORY MANAGEMENT Fixed Partitioning(p294) • Main memory is divided into a number of static partitions at system generation（装入） time. A process may be loaded into a partition of equal or greater size. • The partitions can be equal size or not
Fixed Partitioning Equal size partitions(固定等大小 Inefficient to use main memory, generating internal fragmentation Big program can not be loaded into partition. The size of partition not equal(固定不等大小) Can alleviate(缓解) the disadvantage MEMORY MANAGEMENT
MEMORY MANAGEMENT Fixed Partitioning • Equal size partitions(固定等大小) • Inefficient to use main memory, generating internal fragmentation. • Big program can not be loaded into partition. • The size of partition not equal（固定不等大小） • Can alleviate（缓解）the disadvantage
operating systen operatIng system N S M 2M 4 M S M 8 M & M 12 M S M (a) Equal-slze partitions (b) Unequal-sIze partitions Figure 7.2 Example of Fixed Partitioning of a 64-Mbyte Memor
MEMORY MANAGEMENT