Recent questions tagged memory-management

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1

Galvin, Virtual memory exercise 9.15
A simplified view of thread states is Ready, Running, andBlocked, where a thread is either ready andwaiting to be scheduled, is running on the processor, or is blocked (for example, waiting for I/O). Assuming a thread is in the Running state, ... will change its state from running to waiting. However, I am highly confused over answers to part b, and part c.

asked 3 days ago in Operating System by Harsh Kumar Junior (587 points) | 18 views

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2

Page Table Size of different processes
I have watched two video lectures on OS memory management (PK Biswas and IISc Mathew Jacob). In both lectures they say that the compiler assumes (while compiling and generating the logical addresses to instructions) that for each process, all of the ... table of each process consists of same number of entries..? Is it the real reason to use valid/invalid bit ?

asked 5 days ago in Operating System by Harsh Kumar Junior (587 points) | 23 views

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3

Memory Management and Virtual Memory GATE - 2004

asked Aug 7 in Operating System by nishant279 (439 points) | 15 views

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4

Multilevel Cache Access time
Ans. A

asked Aug 6 in CO & Architecture by Na462 Active (4.5k points) | 45 views

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5

performance cache exercise help
First level data cache: Direct mapping , writeThrough/write allocate , 8kb data and lines of 8 bytes, miss rate= 17% First level instructions cache: Direct mapping,, 4kb data and lines of 8 bytes, miss rate= 2% Second level unified cache: ... accesses to data memory and instructions of the total number of accesses? 5)What is the average memory access time? Thanks !!

asked Aug 3 in CO & Architecture by mauro5991 (25 points) | 13 views

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6

Memory allocation
Consider 900 KB memory is managed using variable partitions but no compaction. It currently has three process occupied partition of sizes 212 KB, 114 KB and 100 KB respectively. What is the smallest allocation request that could be denied?

asked Jul 28 in Operating System by kapilbk1996 (265 points) | 15 views

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7

Size of Page Table (Numerical)
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 page table in the system in bytes is __________________

asked Jul 26 in Operating System by srestha Veteran (91.8k points) | 60 views

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8

Virtual Memory
A computer uses 30 bit physical address, 38 bit virtual address and uses 2-level paging. The page table base register stores the base address of the first level, Each page table, occupied exact one page. Each entry of first level store base address of second level ... second level table store a page table entry which is of size 32 bits. The size of page in KB in computer is ________.

asked Jul 19 in Operating System by Na462 Active (4.5k points) | 58 views

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9

Memory References

asked Jul 19 in Operating System by Na462 Active (4.5k points) | 26 views

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10

Virtual Memory
Which of the following is true? A. If the page size increases page fault rate may also increase. B. Multi-level paging optimizes program execution time. C. Dynamic linking increases program execution time.Correct Option D. TLB is a software data structure.

asked Jul 18 in Operating System by Na462 Active (4.5k points) | 49 views

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11

Virtual Memory
Virtual memory increases degree of multiprogramming Virtual memory decreases degree of multiprogramming Degree of multiprogrammoing means number of process is in memory. (and I think memory here is primary memory and not secondary memory such as disk or magnetic tape) ... memory must decreses use of main memory. But according to prediction it is wrong. Where Am I getting wrong?

asked Jul 12 in Operating System by srestha Veteran (91.8k points) | 121 views

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12

Virtual Memory

asked Jul 12 in Operating System by Na462 Active (4.5k points) | 59 views

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13

Virtual Memory

asked Jul 12 in Operating System by Na462 Active (4.5k points) | 61 views

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14

Made easy workbook
Q-1

asked Jul 7 in Operating System by Avik Chowdhury Junior (737 points) | 45 views

–1 vote

1 answer

15

Made easy workbook
What is the size of largest segment?

asked Jul 7 in Operating System by Avik Chowdhury Junior (737 points) | 39 views

–1 vote

1 answer

16

Made easy Workbook
Q-32

asked Jul 7 in Operating System by Avik Chowdhury Junior (737 points) | 36 views

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2 answers

17

Made easy Workbook
Q-29

asked Jul 7 in Operating System by Avik Chowdhury Junior (737 points) | 37 views

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1 answer

18

Made easy Workbook

asked Jul 7 in Operating System by Avik Chowdhury Junior (737 points) | 23 views

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2 answers

19

Made easy workbook
A System uses a two level page table has 2^12 bytes pages and 32 bit virtual adresses .The first 8 bit of the address serve as a index into the first level page table.For 64 bit virtual addresses,a 4kb page size and 256 mb of RAM an inverted page table requires A)2^40 entries. B)2^52 entries C)2^16 entries. D)2^78 entries

asked Jul 7 in Operating System by Avik Chowdhury Junior (737 points) | 28 views

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20

Doubt of Page Table
Can I calculate Page Table Size by just multiplying No. Of Pages & Frame No. if PTE size is not given?

asked Jul 7 in Operating System by MRINMOY_HALDER (109 points) | 21 views

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21

Memory mapped files
Please explain the concept of memory mapped files in OS. Is it really in GATE 2019 Syllabus?

asked Jun 22 in Operating System by Na462 Active (4.5k points) | 40 views

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22

Virtual memory
How does the virtual memory separates the logical memory as perceived by users from physical memory? Is it because we can load program with larger address space then physical memory but still we need physical memory to load our pages don't we ? Then what does the above statement actually trying to convey ?

asked Jun 20 in Operating System by Na462 Active (4.5k points) | 50 views

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23

Hierarchical Page Table
Given 64 bit logical space, Page Size = $4KB$. Do the three level paging? My Solution:- 1. Since address space is =$ 2^{64} Bytes$ Page size = $2^{12}$ Bytes. Number of entries in third level Page table is :- $2^{64} / 2^{12}$ = $2^ ... at three levels as:- $1st$ level $2nd$ level $3rd$ level Offset $ 32$ $10$ $10$ $12$ Please explain how did they find this out ? Please :)

asked Jun 19 in Operating System by Na462 Active (4.5k points) | 87 views

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24

memory management
A computer whose processes have 1024 pages in their address spaces keeps its page tables in memory. The overhead required for reading a word from the page table is 500 nsec. To reduce this overhead, the computer has an associative memory which holds 32 (virtual page, ... frame) pairs and can do look up in 100 nsec. What hit rate is needed to reduce the mean overhead to 200 nsec?

asked Jun 8 in Operating System by priyanka manwani (61 points) | 59 views

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25

self- doubt
when the process completes its execution then 1. its some pages still present in a frame(main memory) and replace according to demand 2. all of sudden all the pages erase out from main memory after process completion. Which statement is true?

asked Apr 30 in Operating System by Raj Kumar 7 Active (1k points) | 51 views

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26

Paging
In multi-level paging, a big page table is divided into smaller pages and for those pages (of main page table) a new page table is created. So what be basically did is broke down the main page table into small pieces (usually so to reduce the size of parts to page size). But, the overall size of the main page table remain same, right? Then what actually is the benefit of multilevel paging?

asked Apr 27 in Operating System by Ankit Sahu (73 points) | 137 views

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27

Logical Address in Paging
In paging, we know that the no. of bits for page offset is same and depends upon the size of the page size. However, the rest of the bits of the logical address somehow determines the no. of pages of the process and thus the size of ... offset (constant) ) and thus two process of different sizes have different length logical addresses? Is it the scenario where we use PTLR?

asked Apr 17 in Operating System by Harsh Kumar Junior (587 points) | 74 views

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28

Self doubt
Explain Last In First Out (LIFO) and MRU with this example and find a number of a page fault. Question: Let the number of the frame in main memory is 5. Reference String: 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10

asked Apr 13 in Operating System by Raj Kumar 7 Active (1k points) | 39 views

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29

self - doubt
Physical memory are divide into frame. The frame of each size are equal. Is the word size in each frame same or it may possible to different in size ? (I am taking about word size in two different frame in main memory. )

asked Apr 8 in Operating System by Raj Kumar 7 Active (1k points) | 33 views

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30

DMRC AM-IT, Virtual memory
The lookup page table shown below is for a job in a paged virtual storage system with a page size of 1024 locations. Each virtual address is in the form [p,d] where p is page number and d is displacement in the page. Virtual page Actual page 0 3 1 --- 2 4 3 0 A virtual address of [0,514] maps to an actual address of A) 512 B)1538 C)3586 D)4514

asked Mar 31 in Operating System by Lalit Verma (33 points) | 131 views

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