GATE CSE
Operating Systems
Memory Management
Previous Years Questions

## Marks 1

Which one of the following statements is FALSE?
Consider a demand paging system with four page frames (initially empty) and LRU page replacement policy. For the following page reference string 7, 2,...
Consider allocation of memory to a new process. Assume that none of the existing holes in the memory will exactly fit the process's memory requirement...
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 ...
A computer system implements a $$40$$-bit virtual address, page size of $$8$$ kilobytes, and a $$128$$-entry translation look-aside buffer $$(TLB)$$ o...
Consider a system with byte-addressable memory, 32-bit logical addresses, 4 kilobyte page size and page table entries of 4 bytes each. The size of the...
A system uses $$3$$ page frames for storing process pages in main memory. It uses the Least Recently Used $$(LRU)$$ page replacement policy. Assume th...
A system uses FIFO policy for page replacement. It has $$4$$ pages frames with no pages loaded to begin with. The system first accesses $$100$$ distin...
In which one of the following page replacement policies, Belady’s anomaly may occur?
The essential content(s) in each entry of a page table is / are:
How many $$32K\,\, \times \,\,1RAM$$ chips are needed to provide a memory capacity of $$256$$ $$K$$-bytes?
What is the swap space in the disk used for?
Consider a program $$P$$ that consists of two source modules $${M_1}$$ and $${M_2}$$ contained in two different files. If $${M_1}$$ contains a referen...
Which of the following addressing modes are suitable for program relocation at run time? $$1.$$ Absolute addressing $$2.$$ Based addressing $$3.$$ Rel...
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 ...
Which of the following is not a form of memory?
The optimal page replacement algorithm will select the page that.
Which of the following statements is false?
The process of assigning load addresses to the various parts of the program and adjusting the code and date in the program to reflect the assigned add...
Consider a virtual memory system with $$FIFO$$ page replacement policy. For an arbitrary page access pattern, increasing the number of page frames in ...
In a resident $$–OS$$ computer, which of the following systems must reside in the main memory under all situations?
Locality of reference implies that the page reference being made by a process
Thrashing
Dirty bit for a page in a page table
A ROM is sued to store the table for multiplication of two $$8$$-bit unsigned integers. The size of ROM required is
In a paged segmented scheme of memory management, the segment table itself must have a page table because:
The principle of locality justifies the use of
A linker is given object modules for a set of programs that were compiled separately. What information need to be included in an object module?
Which page replacement policy sometimes leads to more page faults when size of memory is increased?

## Marks 2

In the context operating systems, which of the following statements is/are correct with respect to paging?
Consider a paging system that uses a 1-level page table residing in main memory and a TLB for address translation. Each main memory access takes 100 n...
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....
Consider a process executing on an operating system that uses demand paging. The average time for a memory access in the system is $$M$$ units if the ...
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 pe...
Consider a computer system with ten physical page frames. The system is provided with an access sequence $$\left( {{a_1},{a_2},....,{a_{20}},{a_1},{a_... A computer system implements$$8$$kilobyte pages and a$$32$$-bit physical address space. Each page table entry contains a valid bit, a dirty bit, th... Consider six memory partitions of sizes$$200KB,400KB,600KB,500KB,300KB$$and$$250KB,$$where$$KB$... A computer has twenty physical page frames which contain pages numbered $$101$$ through $$120.$$ Now a program accesses the pages numbered $$1, 2, …, ... Consider a paging hardware with a TLB. Assume that the entire page table and all the pages are in the physical memory. It takes 10 milliseconds to sea... Assume that there are$$3$$page frames which are initially empty. If the page reference string is$$1, 2, 3, 4, 2, 1, 5, 3, 2, 4, 6,$$the number of ... Consider the virtual page reference string$$$1,2,3,2,4,1,3,2,4,1$$On a demand paged virtual memory system running on a computer system that has ma... Consider the virtual page reference string$$1,2,3,2,4,1,3,2,4,1$$On a demand paged virtual memory system running on a computer system that has ma... A multilevel page table is preferred in comparison to a single level page table for translating virtual address to physical address because. A processor uses 36 bit physical addresses and 32 bit virtual addresses, with a page frame size of 4 Kbytes. Each page table entry is of size 4 bytes.... A virtual memory system uses First In First Out (FIFO) page replacement policy and allocates a fixed number of frames to a process. Consider the follo... A process has been allocated$$3$$page frames. Assume that none of the pages of the process are available in the memory initially. The process makes ... A process has been allocated$$3$$page frames. Assume that none of the pages of the process are available in the memory initially. The process makes ... A Computer system supports$$32$$-bit virtual addresses as well as$$32$$-bit physical addresses. Since the virtual address space is of the same size ... Consider a System with a two-level paging scheme in which a regular memory access takes$$150$$nanoseconds, and servicing a page fault takes$$8$$mi... Which of the following is NOT an advantage of using shared, dynamically linked libraries as opposed to using statically linked libraries? A processor uses$$2$$-level page tables for virtual to physical address translation. Page tables for both levels are stored in the main memory. Virtu... A processor uses$$2$$-level page tables for virtual to physical address translation. Page tables for both levels are stored in the main memory. Virtu... Dynamic linking can cause security concerns because Consider a machine with 64 MB physical memory and a 32-bit virtual address space. If the page size is 4KB, what is the approximate size of the page ta... Suppose the time to service a page fault is on the average$$10$$milliseconds, while a memory access takes$$1$$microsecond. Then a$$99.99$$% hit r... Which of the following is/are advantage of virtual memory? The overlay tree for a program is as shown below: What will be the size of the partition (in physical memory) required to load (and run) this prog... If an instruction takes$${\rm I}$$microseconds and a page fault takes an additional$$j$$microseconds, the effective instruction time if on the ave... A$$1000$$Kbyte memory is managed using variable partitions but to compaction. It currently has two partitions of sizes$$200$$Kbytes and$$260$$Kb... The address sequence generated by tracing a particular program executing in a pure demand paging system with$$100$$records per page with$$1$$free ... In a virtual memory system the address space specified by the address lines of the$$CPU$$must be __________ than the physical memory size and ______... The capacity of a memory unit is defined by the number of words multiplied by the number of bits/word. How many separate address and data lines are ne... A memory page containing a heavily used variable that was initialized very early and is in constant use is removed when Consider the following heap (Figure) in which blank regions are not in use and hatched region are in use. The sequence of requests for blocks of siz... A part of the system software, which under all circumstances must reside in the main memory is: A simple two-pass assembler does the following in the first pass: Match the pairs in the following question by writing the corresponding letters only. ... State whether the following statement TRUE or FALSE. The amount of virtual memory available is limited by the availability of secondary storage. ... State whether the following statement TRUE or FALSE. Any implementation of a critical section requires the use of an indivisible machine instruction s... A ''link editor'' is a program that: The total size of address space in a virtual memory systems is limited by State whether the following statement TRUE or FALSE. The best-fit techniques for memory allocation ensures the memory will never be fragmented. State whether the following statement TRUE or FALSE. The use of monitors ensures that no dead -locks will be caused. State whether the following statement TRUE or FALSE. The$$LRU$$page-replacement policy may cause thrashing for some type of programs. Match the pairs in the following Question.$$\eqalign{ & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,List:\,{\rm I} \cr & \left( A \right)\,\,Criotica... State whether the following statements are TRUE or FALSE with reason. Transferring data in blocks from the main memory to the cache memory enables an ... Under paged memory management scheme simple lock and key memory protection arrangement may still be required if the $$........$$ processors do not ha... 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 memo... State whether the following statements are TRUE or FALSE with reason. The Link-load -and-go loading scheme required less storange space than the Link-... Match the pairs in the following question. List - $${\rm I}$$ $$(A)$$$$\,\,\,\,$$ Virtual Memory $$(B)$$$$\,\,\,\,$$ Shared memory $$(C)$$$$\,\,\,\,$$... ## Marks 5 A computer system uses $$32$$-bit virtual address, and $$32$$-bit physical address. The physical memory is byte addressable, and the page size is $$4... A certain computer system has the segmented paging architecture for virtual memory. The memory is byte addressable. Both virtual and physical address ... In a computer system where the ‘best-fit’ algorithm is used for allocating ‘jobs’ to ‘memory partitions’, the following situation was encountered: ... A demand paged virtual memory system uses$$16$$bit virtual address, page size of$$256$$bytes, and has$$1$$Kbyte of main memory.$$LRU$$page rep... A computer installation has 1000K of main memory. The jobs arrive and finish in the following sequence. Job 1 requiring 200k arrives Job 2 requiring 3... The following page addresses, in the given sequence, were generated by a program: 1 2 3 4 1 3 5 2 1 5 4 3 2 3 This program is run on a demand paged v... Let the page reference and the working set window be c c d b c e c e a d and 4, respectively. The initial working set at time$$t = 0\$ contains the p...
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