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Recent questions tagged memory-management

2 votes
3 answers
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A CPU generates $32$-bit virtual addresses. The page size is $4$ KB. The processor has a Translation Look-aside Buffer (TLB) which can hold a total of $128$ page table entries and is $4$-way set associative. The minimum size of the TLB tag is $\text{11 bits}$ $\text{13 bits}$ $\text{15 bits}$ $\text{20 bits}$
asked Mar 30 in Operating System Lakshman Patel RJIT 158 views
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A memory management system has $64$ pages with $512$ bytes page size. Physical memory consists of $32$ page frames Number of bits required in logical and physical address are respectively: $14$ and $15$ $14$ and $29$ $15$ and $14$ $16$ and $32$
asked Mar 24 in Operating System jothee 307 views
2 votes
3 answers
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What is compaction refers to a technique for overcoming internal fragmentation a paging technique a technique for overcoming external fragmentation a technique for compressing the data
asked Jan 13 in Operating System Satbir 826 views
3 votes
3 answers
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Consider the following page reference string. $1\ 2\ 3\ 4\ 2\ 1\ 5\ 6\ 2\ 1\ 2\ 3\ 7\ 6\ 3\ 2\ 1\ 2\ 3\ 6\ $ What are the minimum number of frames required to get a single page fault for the above sequence assuming LRU replacement strategy? $7$ $4$ $6$ $5$
asked Jan 13 in Operating System Satbir 1.2k views
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What would happen if the bitmap or free list containing the information about free disk blocks was completely lost due to a crash? Is there any way to recover from this disaster, or is it bye-bye disk? Discuss your answers for $UNIX$ and the $FAT -16$ file system separately.
asked Oct 27, 2019 in Operating System Lakshman Patel RJIT 60 views
0 votes
1 answer
12
The beginning of a free-space bitmap looks like this after the disk partition is first formatted$:\: 1000\: 0000\: 0000\: 0000$ (the first block is used by the root directory). The system always searches for free blocks starting at the lowest-numbered block, so after writing ... $A$ is deleted. File $C$ is written, using eight blocks. File $B$ is deleted.
asked Oct 27, 2019 in Operating System Lakshman Patel RJIT 167 views
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1 answer
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Free disk space can be kept track of using a free list or a bitmap. Disk addresses require $D$ bits. For a disk with $B$ blocks, $F$ of which are free, state the condition under which the free list uses less space than the bitmap. For $D$ having the value $16$ bits, express your answer as a percentage of the disk space that must be free.
asked Oct 27, 2019 in Operating System Lakshman Patel RJIT 59 views
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For a given class, the student records are stored in a file. The records are randomly accessed and updated. Assume that each student’s record is of fixed size. Which of the three allocation schemes (contiguous, linked and table/indexed) will be most appropriate?
asked Oct 27, 2019 in Operating System Lakshman Patel RJIT 54 views
0 votes
1 answer
19
One way to use contiguous allocation of the disk and not suffer from holes is to compact the disk every time a file is removed. Since all files are contiguous, copying a file requires a seek and rotational delay to read the file, followed by the transfer at full speed. Writing ... back to the disk at a new location? Using these numbers, how long would it take to compact half of a $16-GB$ disk?
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 45 views
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20
Write a program that can be used to compare the effectiveness of adding a tag field to $TLB$ entries when control is toggled between two programs. The tag field is used to effectively label each entry with the process id. Note that a nontagged $TLB$ can be ... your simulation behaves as expected for a simple (but nontrivial) input example. Plot the number of $TLB$ updates per $1000$ references.
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 76 views
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21
Write a program that will demonstrate the difference between using a local page replacement policy and a global one for the simple case of two processes. You will need a routine that can generate a page reference string based on a statistical model. This model has $N$ ... a global policy instead of a local one. Also, contrast the per-process page fault rate with that of the local policy approach.
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 56 views
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22
Write a program that demonstrates the effect of $TLB$ misses on the effective memory access time by measuring the per-access time it takes to stride through a large array. Explain the main concepts behind the program, and describe what you expect the output to ... . Repeat part $(b)$ but for an older computer with a different architecture and explain any major differences in the output.
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 99 views
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23
Write a program that simulates a toy paging system that uses the $\text{WSClock}$ algorithm. The system is a toy in that we will assume there are no write references (not very realistic), and process termination and creation are ignored (eternal life). The ... per $1000$ memory references. Explain what is needed to extend the program to handle a page reference stream that also includes writes.
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 90 views
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24
Write a program that simulates a paging system using the aging algorithm. The number of page frames is a parameter. The sequence of page references should be read from a file. For a given input file, plot the number of page faults per $1000$ memory references as a function of the number of page frames available.
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 125 views
0 votes
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25
Plot a histogram and calculate the mean and median of the sizes of executable binary files on a computer to which you have access. On a Windows system, look at all .exe and .dll files; on a UNIX system look at all executable files in /bin, /usr/bin, ... assumption about the size of a page table entry. Assume that all programs are equally likely to be run and thus should be weighted equally.
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 59 views
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26
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We consider a program which has the two segments shown below consisting of instructions in segment $0,$ and read/write data in segment $1.$ Segment $0$ has read/execute protection, and segment $1$ has just read/write protection. The memory system is a demand- paged virtual memory system ... $16$ Fetch from segment $1,$ page $4,$ offset $28$ Jump to location in segment $1,$ page $3,$ offset $32$
asked Oct 26, 2019 in Operating System Lakshman Patel RJIT 202 views
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