Placement(放置) Algorithm(p295) s If the partitions is equal size. just choose a free partitions to place a process. lf the partitions is not equal size, using the following tow methods: To guarantee the choosing partition can be the best suitable size one(最佳) To guarantee the choosing partition can contain the correspond process MEMORY MANAGEMENT
MEMORY MANAGEMENT Placement (放置) Algorithm（p295） ❖ If the partitions is equal size. Just choose a free partitions to place a process. ❖ If the partitions is not equal size, using the following tow methods: ٭ To guarantee the choosing partition can be the best suitable size one（最佳）. ٭ To guarantee the choosing partition can contain the correspond process
Operating Operating System System ■■■■■ New L■L rocesses □■■■■■ ■■■ (a)One process queue per partition (b) Single process queue Figure 7.3 Memory assignment for Fixed Partitioning
MEMORY MANAGEMENT
Adv. of fixed partition Simple to implement System spending(开销) is smal MEMORY MANAGEMENT
MEMORY MANAGEMENT Adv. of fixed partition • Simple to implement • System spending(开销) is small
Disadv of Fixed Partition(p296) Having internal fragment(内碎片), inefficient to use main memory. Can not run big size program. The number of process is fixed by the number of partition. MEMORY MANAGEMENT
MEMORY MANAGEMENT Disadv. of Fixed Partition(p296) • Having internal fragment（内碎片）, inefficient to use main memory. • Can not run big size program. • The number of process is fixed by the number of partition
Dynamic Partitioning(动态分区p296) The number and size(数目和大小) of partition is change while the processes are in and out from main memory MEMORY MANAGEMENT
MEMORY MANAGEMENT Dynamic Partitioning(动态分区p296) • The number and size(数目和大小) of partition is change while the processes are in and out from main memory