34 single partition allocation
- 1. Storage Management • Single Partition Allocation 1
- 2. HOME PREVIOUS TOPIC NEXT PREVIOUS QUESTION PAPERS FOR OS CPP TUTORIALS 2
- 3. Recap In the last class, you have learnt Logical address Vs physical address Swapping 3
- 4. Objectives On completion of this period, you would be able to know • Single partition allocation 4
- 5. Single Partition Allocation This is the simplest form of memory management No protection, no utilities, no overhead Used by hardware diagnostics, by system boot code, real time / dedicated systems Logical == Physical User can have complete control 5
- 6. Single Partition Allocation Definition of Partition: Division of Physical memory into fixed sized regions (Allows address spaces to be distinct) The number of partitions determines the level of multiprogramming Partition is given to a process when it's scheduled Memory is divided in to two partitions One for OS and other for User process 6
- 7. Single Partition Allocation 0 Operating system User Free 512 7
- 8. Single Partition Allocation O OS must reside in low memory where interrupt vectors are placed, user processes are executing in high memory Must protect the OS code changes by user process and vice versa Relocation-register scheme used to protect user processes from each other and from changing operating-system code and data 8
- 9. Single Partition Allocation • Relocation register contains value of smallest “physical address” • Limit register contains range of “logical address” • Each “Logical address” must be less than the limit register • MMU maps the logical address dynamically by adding the value of relocation register. • Concept of mapping address shown in next slide 9
- 10. Hardware Support for Relocation and Limit Registers 10
- 11. Single Partition Allocation Limit Relocation Register Register Yes CPU < + MEMORY Logical Physical Address No Address Trap; addressing error 11
- 12. Summary In this class, you have learnt Single partition allocation The simplest form of memory management Used by hardware diagnostics, by system boot code, real time / dedicated systems Hard ware support for relocation and limit register 12
- 13. Frequently Asked Questions 1. Explain about single partition allocation ? 13
- 14. Quiz 1. Division of physical memory into fixed sized regions a) Words b) Partition c) Bits d) None 14
- 15. Quiz 2. Relocation register contains value of smallest ____________address a) Physical b) Logical c) Absolute d) None 15
- 16. Quiz 3. ____________scheme used to protect user processes from each other a) Relocation-register b) Symbolic c) Logical d) None 16
- 17. Quiz 4. In single partition scheme memory is divided into __________ partitions a) one b) two c) three d) None 17
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