Exam 3: Memory Management: Virtual Memory

The optimal selection of cache size and replacement algorithm can result in 80 to 90 percent of all requests being in the cache.

To find the exact position of an instruction in memory, after the page number has been calculated, the operating system refers to the job's PMT to find out which page frame contains the page.

A variation of the LRU page replacement algorithm is known as the clock page replacement policy because it is implemented with a circular queue and uses a pointer to step through the reference bits of the active pages, simulating a clockwise motion.

The ____ policy is based on the theory that the best page to remove is the one that has been in memory the longest.

Consider the following page fault handler algorithm. Replace the * in the algorithm with ____. 1 If there is no free page frame Then Select page to be swapped out using page removal algorithm Update job's Page Map Table If content of page had been changed then * End if End if 2 Use page number from step 3 from the Hardware Instruction Processing Algorithm to get disk address where the requested page is stored 3 Read page into memory 4 Update job's Page Map Table 5 Update Memory Map Table 6 Restart interrupted instruction

During the second generation, programmers started dividing their programs into sections that resembled working sets, really segments, originally called roll in/roll out and now called ____.

A page interrupt is generated when a new page is brought into memory.

Assume that the Page Map Table below is in effect. The number of lines per page is 400. The actual memory location for line 433 is ____. Job Page Number   Page Frame Number 0                                   8 1                                   10 2                                   5 3                                  11

Studies have shown that having any ____, even a small one, can substantially improve the performance of the computer system.

The process of shifting bits to the right and resetting the leftmost bit to 1 when a page is referenced gives a history of each page's usage.

If a particular demand paging configuration has 9 page interrupts out of 11 page requests, failure rate is ____.

Assume that four page frames are available and are numbered 1-4. Pages A-D have been loaded into page frames 1-4 in order. Assume that page E is requested.The page frame to be loaded into when the FIFO algorithm is used is ____.

When using a FIFO scheme, more memory will always result in better performance.

When using the clock replacement policy, a page with a reference bit of ____ is replaced.

The primary advantage of storing programs in noncontiguous locations is that ____.

One sector will hold one page of job instructions and fit into one page frame of memory.

When there is an excessive amount of page swapping between main memory and secondary storage, the operation becomes inefficient, which is called ____.

If the page size is 100 lines,____ is the displacement for line 214 of a program.

To move in a new page, a resident page must be swapped back into primary storage.

Demand paging requires that the Page Map Table for each job keep track of each page as it is loaded or removed from main memory.