Across
- 3. a fixed time slice allocated to a process.
- 5. occurs when a requested page is not in memory and a free page cannot be used to satisfy allocation.
- 7. occurs when a new page is referred but is not yet in memory.
- 8. data structure used to implement an interrupt vector table.
- 10. this is a memory cache which can reduce the time taken to access a user memory location; it is part of the memory management unit.
- 11. problem resulting from use of virtual memory. Excessive swapping in and out of virtual memory leads to a high rate of hard disk read/write head movements thus reducing processing speed.
- 13. form of memory management which divides up physical memory and logical memory into fixed-size memory blocks.
- 14. method by which a system assigns a processor to a task or process based on the priority level.
- 16. term used to describe a page in memory that has been modified.
- 18. a small program that is used to load other programs to ‘start up’ a computer.
- 21. process manager which handles the removal of running programs from the CPU and the selection of new processes.
- 23. fixed-size logical memory blocks.
- 24. the core of an OS with control over process management, memory management, interrupt handling, device management and I/O operations.
- 28. point at which the execution of a process comes to a halt since the system is busier paging in/out of memory rather than actually executing them.
- 30. main/primary RAM memory.
- 33. table that maps logical addresses to physical addresses; it contains page number, flag status, frame address and time of entry.
- 34. running, ready and blocked; the states of a process requiring execution.
- 35. variable-size memory blocks into which logical memory is split up.
- 36. to constantly deprive a process of the necessary resources to carry out a task/process.
- 37. type of paging that gives the illusion of unlimited memory being available.
- 38. data structure which contains all the data needed for a process to run.
Down
- 1. device that allows certain hardware to access RAM independently of the CPU.
- 2. procedure by which, when the next process takes control of the CPU, its previous state is reinstated or restored.
- 4. function allowing a computer to process more than one task/process at a time.
- 6. page replacement algorithm in which the page which has not been used for the longest time is replaced.
- 9. space on HDD used in virtual memory, which saves process data.
- 12. values given to interrupts based on values 0 to 31.
- 15. the time when a process has control of the CPU.
- 17. fixed-size physical memory blocks.
- 19. function of memory management deciding which processes should be in main memory and where they should be stored.
- 20. scheduling algorithm that uses time slices assigned to each process in a job queue.
- 22. page replacement that keeps track of all pages in memory using a queue structure. The oldest page is at the front of the queue and is the first to be removed when a new page is added.
- 25. – type of scheduling in which a process terminates or switches from a running state to a waiting state.
- 26. the address space that an OS perceives to be main storage.
- 27. phenomenon which means it is possible to have more page faults when increasing the number of page frames. Optimal page replacement – page replacement algorithm that looks forward in time to see which frame to replace in the event of a page fault.
- 29. a program that has started to be executed.
- 30. type of scheduling in which a process switches from running state to steady state or from waiting state to steady state.
- 31. a form of data swapping where pages of data are not copied from HDD/SSD into RAM until they are actually required.
- 32. index number of a segment.
- 35. table containing the segment number, segment size and corresponding memory location in physical memory: it maps logical memory segments to physical memory.