第三章作业
4、Consider a s a system in which memory consists of the following hole sizes in memory order: 10KB, 4KB, 20KB, 18KB, 7KB, 9KB, 12KB and 15KB. Which hole is taken for successive segment requests of
(a) 12KB (b) 10KB (c)9KB
For first fie? Now repeat the question for best fit, worst fit and next fit. Solution: First fit
Next fit
Best fit
Worst fit
5、For each of the following decimal virtual addresses, compute the virtual page number and offset for a 4-KB page and for an 8-KB page: 20000, 32768, 60000. Solution:
page size: 4K=4*1024=4096
(1) 20000/4096=4...3616 page number is 4, offset is 3616 (2) 32768/4096=8 page number is 8, offset is 0 (3) 60000/4096=14 (2656)
page number is 14, offset is 2656
page size: 8K=8*1024=8192
(1)20000/8192=2…3616 page number is 2, offset is 3616
(2)32768/8192=4 page number is 4 offset is 0
(3)60000/8192=7…2656 page number is 7, offset is 2656
22. If FIFO page replacement is used with four page frames and eight pages, how many page faults will occur with the reference string 017237103 if the four frames are initially empty? Now repeat this problem for LRU.
Solution:
28. A computer has four page frames. The time of loading, time of last access, and the R and M
(a)Which page will NRU replace?
(b)Which page will FIFO replace?
(c)Which page will LRU replace?
(d)Which page will second chance replace?
Solution:
(a) Page 2 (2) (b) Page 3 (3) (c) Page 1 (1) (d) Page 2 (2)
