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- 1If a system is not in a safe state, will it deadlock?Maybe
- 2at T0: 3 drives are available. Is the system in a safe state?Yes (safe state: ).
-P1 can be given 2 tape drives
-When P1 releases its resources; there are 5 drives
- P0 uses 5 and subsequently releases them.
- P2 can then proceed. - 3What is the resource allocation graph algorithm?A deadlock avoidance algorithm where only one instance of each resource type is available:
- 4What is Banker's algorithm?A deadlock avoidance algorithm for multiple instances of each type. Uses Available, Max, Allocation, and Need Vectors:
- 5How do you detect deadlocks?Single instance of each resource: use wait-for graph.
Multiple instances: variation of baker's. - 6What is Dynamic Loading, Linking, and Swapping?Dynamic loading: Routine is not loaded until it is called.
Dynamic linking: Linking postponed until execution time.
Swapping: a process can be swapped temporarily out of memory to a backing store and then brought back into memory for continued execution. - 7How is a page table implemented?Page table is kept in main memory:
-Page-table base register (PTBR) points to the page table,
-length register (PTLR) indicates size of page table.
Every data/instruction access requires 2 memory accesses:
-1 for page table, 1 for data/instruction.
- Two-memory access problem is solved by use of special fast-lookup hardware cache (i.e. cache page table in registers.): Associative registers or TLBs. - 8What is a diagram for page tables?
- 9How do you calculate effective access time?
- 10What are the different paging methods?
- 11What is the diagram that shows how a page table accesses memory?
- 12What are the advantages of virtual memory?- Separation of user logical memory from physical memory.
- Only PART of the program needs to be in memory or execution.
- Logical address space can therefor be much larger than physical address space.
- Need to allow pages to be swapped in and out.
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- Computer Science Flashcards on Untitled, created by Dylan Whitehurst on 06/05/2022.
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- Dylan Whitehurst
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