Virtual Memory

A system has a Translation Lookaside Buffer (TLB) that has a reach of 1 MB . TLB reach is defined as the total amount of physical memory that can be accessed through the TLB entrie...

In optimal page replacement algorithm, information about all future page references is available to the operating system (OS). A modification of the optimal page replacement algori...

Which of the following tasks is/are the responsibility/responsibilities of the memory management unit (MMU) in a system with paging-based memory management?

Consider a memory management system that uses a page size of 2 KB. Assume that both the physical and virtual addresses start from 0. Assume that the pages 0, 1, 2, and 3 are stored...

Consider a computer system with 57-bit virtual addressing using multi-level tree-structured page tables with L levels for virtual to physical address translation. The page size is...

Assume that in a certain computer, the virtual addresses are 64 bits long and the physical addresses are 48 bits long. The memory is word addressable. The page size is 8 kB and the...

In which one of the following page replacement algorithms it is possible for the page fault rate to increase even when the number of allocated frames increases?

Consider a computer system with $$40$$-bit virtual addressing and page size of sixteen kilobytes. If the computer system has a one-level page table per process and each page table...

Consider a main memory with five page frames and the following sequence of page references: 3, 8, 2, 3, 9, 1, 6, 3, 8, 9, 3, 6, 2, 1, 3. Which one of the following is true with res...

A system uses $$3$$ page frames for storing process pages in main memory. It uses the Least Recently Used $$(LRU)$$ page replacement policy. Assume that all the page frames are ini...

Assume that there are $$3$$ page frames which are initially empty. If the page reference string is $$1, 2, 3, 4, 2, 1, 5, 3, 2, 4, 6,$$ the number of page faults using the optimal...

A thread is usually defined as a ''light weight process'' because an operating system $$(OS)$$ maintains smaller data structures for a thread than for a process. In relation to thi...

A system uses FIFO policy for page replacement. It has $$4$$ pages frames with no pages loaded to begin with. The system first accesses $$100$$ distinct pages in some order and the...

Consider the virtual page reference string $$$1,2,3,2,4,1,3,2,4,1$$$ On a demand paged virtual memory system running on a computer system that has main memory size of $$3$$ page fr...

In which one of the following page replacement policies, Belady’s anomaly may occur?

A process has been allocated $$3$$ page frames. Assume that none of the pages of the process are available in the memory initially. The process makes the following sequence of page...

A process has been allocated $$3$$ page frames. Assume that none of the pages of the process are available in the memory initially. The process makes the following sequence of page...

A Computer system supports $$32$$-bit virtual addresses as well as $$32$$-bit physical addresses. Since the virtual address space is of the same size as the physical address space,...

Increasing the $$RAM$$ of a computer typically improves performance because

What is the swap space in the disk used for?

Consider the following code fragment: if (fork() == 0) { a = a + 5; printf("%d, %d \n", a, &a); } else { a = a - 5; printf ("%d, %d \n", a, &a); } Let $$u,v$$ be the values printed...

The minimum number of page frames that must be allocated to a running process in a virtual memory environment is determined by.

In a system with $$32$$ bit virtual addresses and $$1$$ $$KB$$ page size, use of one-level page tables for virtual to physical address translation is not practical because of

A processor uses $$2$$-level page tables for virtual to physical address translation. Page tables for both levels are stored in the main memory. Virtual and physical addresses are...

A processor uses $$2$$-level page tables for virtual to physical address translation. Page tables for both levels are stored in the main memory. Virtual and physical addresses are...

The optimal page replacement algorithm will select the page that.

Where does the swap space reside?

Which of the following statements is false?

Consider a virtual memory system with $$FIFO$$ page replacement policy. For an arbitrary page access pattern, increasing the number of page frames in main memory will

Suppose the time to service a page fault is on the average $$10$$ milliseconds, while a memory access takes $$1$$ microsecond. Then a $$99.99$$% hit ratio results in average memory...

Which of the following is/are advantage of virtual memory?

Listed below are some operating system abstractions (in the left column) and the hardware components. Which matching pairs is correct? $$\,\,\,\,\,\,\,\,\,\,$$$$\,\,\,\,\,\,\,\,\,\...

A certain computer system has the segmented paging architecture for virtual memory. The memory is byte addressable. Both virtual and physical address spaces contain $${2^{16}}$$ by...

If an instruction takes $${\rm I}$$ microseconds and a page fault takes an additional $$j$$ microseconds, the effective instruction time if on the average a page fault occurs every...

Dirty bit for a page in a page table

Locality of reference implies that the page reference being made by a process

The address sequence generated by tracing a particular program executing in a pure demand paging system with $$100$$ records per page with $$1$$ free main memory frame is recorded...

In a virtual memory system the address space specified by the address lines of the $$CPU$$ must be __________ than the physical memory size and _______ than the secondary storage s...

A memory page containing a heavily used variable that was initialized very early and is in constant use is removed when

Let the page reference and the working set window be c c d b c e c e a d and 4, respectively. The initial working set at time $$t = 0$$ contains the pages {a, d, e}, where a was re...

Which page replacement policy sometimes leads to more page faults when size of memory is increased?

State whether the following statement TRUE or FALSE. The amount of virtual memory available is limited by the availability of secondary storage.

State whether the following statement TRUE or FALSE. The $$LRU$$ page-replacement policy may cause thrashing for some type of programs.

The total size of address space in a virtual memory systems is limited by

In a two -level virtual memory, the memory access time for main memory, $${t_M} = {10^{ - 8}}\sec $$ and the memory access time for the secondary memory, tag $$ = {10^{ - 3}}.$$ Wh...