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Recent questions tagged memory-management
9
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121
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 25 (Page No. 334)
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 ... five blocks. File $A$ is deleted. File $C$ is written, using eight blocks. File $B$ is deleted.
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 direc...
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Oct 27, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
descriptive
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122
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 24 (Page No. 334)
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 ... For $D$ having the value $16$ bits, express your answer as a percentage of the disk space that must be free.
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 conditio...
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admin
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Oct 27, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
descriptive
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123
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 23 (Page No. 334)
Consider a $4-TB$ disk that uses $4-KB$ blocks and the free-list method. How many block addresses can be stored in one block?
Consider a $4-TB$ disk that uses $4-KB$ blocks and the free-list method. How many block addresses can be stored in one block?
admin
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admin
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Oct 27, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
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124
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 22 (Page No. 334)
Explain how hard links and soft links differ with respective to i-node allocations.
Explain how hard links and soft links differ with respective to i-node allocations.
admin
332
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admin
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Oct 27, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
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125
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 18 (Page No. 334)
Consider a file whose size varies between $4\: KB$ and $4\: MB$ during its lifetime. Which of the three allocation schemes (contiguous, linked and table/indexed) will be most appropriate?
Consider a file whose size varies between $4\: KB$ and $4\: MB$ during its lifetime. Which of the three allocation schemes (contiguous, linked and table/indexed) will be ...
admin
601
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admin
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Oct 27, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
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126
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 17 (Page No. 334)
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?
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...
admin
461
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admin
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Oct 27, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
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127
Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 15 (Page No. 333)
Some digital consumer devices need to store data, for example as files. Name a modern device that requires file storage and for which contiguous allocation would be a fine idea.
Some digital consumer devices need to store data, for example as files. Name a modern device that requires file storage and for which contiguous allocation would be a fin...
admin
222
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
file-system
memory-management
contiguous-allocation
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 4 Question 13 (Page No. 333)
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 ... a new location? Using these numbers, how long would it take to compact half of a $16-GB$ disk?
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 ...
admin
968
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
file-system
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129
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 55 (Page No. 261 - 262)
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 ... for a simple (but nontrivial) input example. Plot the number of $TLB$ updates per $1000$ references.
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 t...
admin
363
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
translation-lookaside-buffer
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130
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 54 (Page No. 261)
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 ... a local one. Also, contrast the per-process page fault rate with that of the local policy approach.
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 ...
admin
301
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
page-replacement
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131
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 53 (Page No. 261)
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 ... but for an older computer with a different architecture and explain any major differences in the output.
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...
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433
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
virtual-memory
translation-lookaside-buffer
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132
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 52 (Page No. 260 - 261)
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 ... references. Explain what is needed to extend the program to handle a page reference stream that also includes writes.
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...
admin
390
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
page-fault
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133
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 51 (Page No. 260)
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.
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 ...
admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
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134
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 50 (Page No. 260)
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 ... of a page table entry. Assume that all programs are equally likely to be run and thus should be weighted equally.
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 a...
admin
386
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
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135
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 49 (Page No. 260)
Virtual memory provides a mechanism for isolating one process from another. What memory management difficulties would be involved in allowing two operating systems to run concurrently? How might these difficulties be addressed?
Virtual memory provides a mechanism for isolating one process from another. What memory management difficulties would be involved in allowing two operating systems to run...
admin
427
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 48 (Page No. 260)
Can you think of any situations where supporting virtual memory would be a bad idea, and what would be gained by not having to support virtual memory? Explain.
Can you think of any situations where supporting virtual memory would be a bad idea, and what would be gained by not having to support virtual memory? Explain.
admin
433
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
virtual-memory
paging
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137
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 47 (Page No. 259 - 260)
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 ... $1,$ page $4,$ offset $28$ Jump to location in segment $1,$ page $3,$ offset $32$
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 p...
admin
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
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page-fault
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138
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 46 (Page No. 259)
When segmentation and paging are both being used, as in $MULTICS,$ first the segment descriptor must be looked up, then the page descriptor. Does the $TLB$ also work this way, with two levels of lookup?
When segmentation and paging are both being used, as in $MULTICS,$ first the segment descriptor must be looked up, then the page descriptor. Does the $TLB$ also work this...
admin
298
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
segmentation
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 45 (Page No. 259)
Explain the difference between internal fragmentation and external fragmentation. Which one occurs in paging systems? Which one occurs in systems using pure segmentation?
Explain the difference between internal fragmentation and external fragmentation. Which one occurs in paging systems? Which one occurs in systems using pure segmentation?...
admin
920
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
fragmentation
segmentation
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 44 (Page No. 259)
A machine-language instruction to load a $32-bit$ word into a register contains the $32-bit$ address of the word to be loaded. What is the maximum number of page faults this instruction can cause?
A machine-language instruction to load a $32-bit$ word into a register contains the $32-bit$ address of the word to be loaded. What is the maximum number of page faults t...
admin
315
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
page-fault
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 43 (Page No. 259)
A group of operating system designers for the Frugal Computer Company are thinking about ways to reduce the amount of backing store needed in their new operating system. The head guru has just suggested not bothering to save the ... this idea work for the program text? Under what conditions, if any, does it work for the data?
A group of operating system designers for the Frugal Computer Company are thinking about ways to reduce the amount of backing store needed in their new operating system. ...
admin
213
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
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142
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 42 (Page No. 259)
It has been observed that the number of instructions executed between page faults is directly proportional to the number of page frames allocated to a program. If the available memory is doubled, the mean interval between page faults ... page faults, how long would it take to run if twice as much memory were available?
It has been observed that the number of instructions executed between page faults is directly proportional to the number of page frames allocated to a program. If the ava...
admin
640
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
page-fault
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 41 (Page No. 259)
A computer provides each process with $65,536$ bytes of address space divided into pages of $4096$ bytes each. A particular program has a text size of $32,768$ bytes, a data size of $16,386$ bytes, and a stack size of ... it then fit? Each page must contain either text, data, or stack, not a mixture of two or three of them.
A computer provides each process with $65,536$ bytes of address space divided into pages of $4096$ bytes each. A particular program has a text size of $32,768$ bytes, a d...
admin
2.4k
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
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144
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 40 (Page No. 259)
One of the first timesharing machines, the $DEC\: PDP-1,$ had a (core) memory of $4K\: 18-bit$ words. It held one process at a time in its memory. When the scheduler decided to run another process, the process in ... start writing (or reading) at any word, rather than only at word $0.$ Why do you suppose this drum was chosen?
One of the first timesharing machines, the $DEC\: PDP-1,$ had a (core) memory of $4K\: 18-bit$ words. It held one process at a time in its memory. When the scheduler deci...
admin
187
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
page-replacement
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 39 (Page No. 259)
You have been hired by a cloud computing company that deploys thousands of servers at each of its data centers. They have recently heard that it would be worthwhile to handle a page fault at server A by reading ... local disk drive. How could that be done? Under what conditions would the approach be worthwhile? Be feasible?
You have been hired by a cloud computing company that deploys thousands of servers at each of its data centers. They have recently heard that it would be worthwhile to ha...
admin
275
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
page-fault
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146
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 38 (Page No. 258)
Consider the following two-dimensional array: int X[64][64]; Suppose that a system has four page frames and each frame is $128$ words (an integer occupies one word). Programs that manipulate the $X$ array fit into exactly one page and always occupy page $0.$ ... ; i < 64; i++) for (int j = 0; j < 64; j++) X[i][j] = 0;
Consider the following two-dimensional array:int X[64][64];Suppose that a system has four page frames and each frame is $128$ words (an integer occupies one word). Progra...
admin
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admin
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Oct 26, 2019
Operating System
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operating-system
memory-management
page-replacement
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Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 37 (Page No. 258)
Suppose that two processes $A$ and $B$ share a page that is not in memory. If process $A$ faults on the shared page, the page table entry for process $A$ must be updated once the page is read into ... page fault will bring the shared page into memory? Explain. What is the potential cost of delaying the page table update?
Suppose that two processes $A$ and $B$ share a page that is not in memory. If process $A$ faults on the shared page, the page table entry for process $A$ must be updated ...
admin
427
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admin
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Oct 26, 2019
Operating System
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operating-system
memory-management
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148
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 36 (Page No. 258)
A computer has four page frames. The time of loading, time of last access, and the $R$ and $M$ bits for each page are as shown below (the times are in clock ticks): Which page will NRU replace? Which page will FIFO replace? Which page will LRU replace? Which page will second chance replace?
A computer has four page frames. The time of loading, time of last access, and the $R$ and $M$ bits for each page are as shown below (the times are in clock ticks):Which ...
admin
5.3k
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admin
asked
Oct 26, 2019
Operating System
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operating-system
memory-management
page-replacement
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149
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 35 (Page No. 258)
How long does it take to load a $64-KB$ program from a disk whose average seek time is $5\: msec,$ whose rotation time is $5 msec,$ and whose tracks hold $1\: MB$ for a $2-KB$ page size? for a ... around the disk and the number of cylinders is so large that the chance of two pages being on the same cylinder is negligible.
How long does it take to load a $64-KB$ program from a disk whose average seek time is $5\: msec,$ whose rotation time is $5 msec,$ and whose tracks hold $1\: MB$for a $2...
admin
375
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admin
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Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
paging
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150
Andrew S. Tanenbaum (OS) Edition 4 Exercise 3 Question 34 (Page No. 257)
A student has claimed that in the abstract, the basic page replacement algorithms (FIFO, LRU, optimal) are identical except for the attribute used for selecting the page to be replaced.'' What is ... for the FIFO algorithm? LRU algorithm? Optimal algorithm? Give the generic algorithm for these page replacement algorithms.
A student has claimed that ‘‘in the abstract, the basic page replacement algorithms (FIFO, LRU, optimal) are identical except for the attribute used for selecting the...
admin
471
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admin
asked
Oct 26, 2019
Operating System
tanenbaum
operating-system
memory-management
page-replacement
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