9.10 Consider a paging system with the page table stored in memory.
a. If a memory reference takes 200 nanoseconds, how long
does a paged memory reference take?
b. If we add TLBs, and 75 percent of all page-table references are found in the TLBs, what is the effective memory reference time? (Assume that finding a page-table entry in the TLBs takes zero time, if the entry is there.)
9.14 Explain why it is easier to share a reentrant module using segmentation than it is to do so when pure paging is used.
10.2 Assume that you have a page-reference string for a process with m frames (initially all empty). The page-reference string has length p; n distinct page numbers occur in it. Answer these questions for any page-replacement algorithms:
a. What is a lower bound on the number of page faults?
b. What is an upper bound on the number of page faults?
10.9 Consider a demand-paging system with the following time-measured utilizations:
CPU utilization: 20%
Paging disk: 97.7% (demand, not storage)
Other I/O devices: 5%
For each of the following, say whether it will (or is likely to) improve CPU utilization. Briefly explain your answers.
a. Install a faster CPU
b. Install a bigger paging disk
c. Increase the degree of multiprogramming
d. Decrease the degree of multiprogramming
e. Install more main memory
f. Install a faster hard disk, or multiple controllers with multiple hard disks
g. Add prepaging to the page-fetch algorithms
h. Increase the page size
10.19 We have an operating system for a machine that uses base and limit registers, but we have modified the machine to provide a page table. Can we set up the page tables to simulate base and limit registers? How can we do so, or why can we not do so?