Chapter 10 Storage management

1. Chapter 10 Storage management • Elements requiring storage • Programmer and system controlled storage • Static Storage Management • Heap Storage Management

2. Elements requiring storage • Code segments for translated user programs • System run-time programs - e.g. libraries • User defined data structures and constants • Subprogram return points • Referencing environments

3. Elements requiring storage • Temporaries in expression evaluation • Temporaries in parameter transmission • Input-Output buffers • Miscellaneous system data - tables etc

4. Operations that require storage allocation • Subprogram call and return operations - creation and deletion of activation records • Explicit data structure creation and destruction operations • Component insertion and deletion operations

5. Programmer and system controlled storage • Pros and cons: • Programmer knows when to allocate / free storage. • Programmer may interfere with the system-controlled storage management • Storage-Management Phases • Initial allocation • Recovery • Compaction and reuse

6. Static Storage Management • Static allocation : • allocation during translation that remains fixed throughout execution. • Does not allow recursive subprograms

7. Dynamic Allocation:Heap Storage Management Memory used for dynamic allocation of data objects in somewhat unstructured manner is called heap storage. OS HEAP STACK

8. Heap Storage Management • Tasks: • allocation, • recovery, • dangling references • garbage collection • compaction, • reuse • Fixed size elements • Variable size elements

9. Heap Compaction used used used used used used used

10. Heap Compaction used used used used used used used