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Processes, Threads, Inter‐process communication, Concurrency and synchronization. Deadlock. CPU scheduling. Memory management and Virtual memory. File systems. Disks is also under this

$$\small{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count}&2&3&2&2&1&1&1&2&3
\\\hline\textbf{2 Marks Count}&4&3&2&2&4&3&3&3&4
\\\hline\textbf{Total Marks}&10&9&6&6&9&7&\bf{6}&\bf{7.8}&\bf{10}\\\hline
\end{array}}}$$

Recent questions in Operating System

62 votes
3 answers
1
A uni-processor computer system only has two processes, both of which alternate $10$ $\text{ms}$ CPU bursts with $90$ $\text{ms}$ I/O bursts. Both the processes were created at nearly the same time. The I/O of both processes can proceed in ... first scheduling Static priority scheduling with different priorities for the two processes Round robin scheduling with a time quantum of $5$ $\text{ms}$
asked Sep 17, 2014 in Operating System Kathleen 7.4k views
17 votes
6 answers
2
In a system with $\text{32 bit}$ virtual addresses and $\text{1 KB}$ page size, use of one-level page tables for virtual to physical address translation is not practical because of the large amount of internal fragmentation the large amount of external fragmentation the large memory overhead in maintaining page tables the large computation overhead in the translation process
asked Sep 16, 2014 in Operating System Kathleen 5.7k views
33 votes
4 answers
3
Using a larger block size in a fixed block size file system leads to better disk throughput but poorer disk space utilization better disk throughput and better disk space utilization poorer disk throughput but better disk space utilization poorer disk throughput and poorer disk space utilization
asked Sep 16, 2014 in Operating System Kathleen 6.3k views
25 votes
4 answers
4
Consider three CPU-intensive processes, which require $10$, $20$ and $30$ time units and arrive at times $0$, $2$ and $6$, respectively. How many context switches are needed if the operating system implements a shortest remaining time first scheduling algorithm? Do not count the context switches at time zero and at the end. $1$ $2$ $3$ $4$
asked Sep 16, 2014 in Operating System Rucha Shelke 6.4k views
20 votes
3 answers
5
The following solution to the single producer single consumer problem uses semaphores for synchronization. #define BUFFSIZE 100 buffer buf[BUFFSIZE]; int first = last = 0; semaphore b_full = 0; semaphore b_empty = BUFFSIZE void producer() { while(1) { produce an ... $p2$, immediately after $c1$ and immediately before $c2$ so that the program works correctly for multiple producers and consumers.
asked Sep 16, 2014 in Operating System Kathleen 2.5k views
26 votes
3 answers
6
A computer uses $32-bit$ virtual address, and $32-bit$ physical address. The physical memory is byte addressable, and the page size is $4$ $\text{kbytes}$ . It is decided to use two level page tables to translate from virtual address to physical ... entries that can be contained in each page? How many bits are available for storing protection and other information in each page table entry?
asked Sep 16, 2014 in Operating System Kathleen 4.8k views
15 votes
2 answers
7
Draw the process state transition diagram of an OS in which (i) each process is in one of the five states: created, ready, running, blocked (i.e., sleep or wait), or terminated, and (ii) only non-preemptive scheduling is used by the OS. Label the transitions appropriately.
asked Sep 16, 2014 in Operating System Kathleen 2.3k views
34 votes
4 answers
8
Which combination of the following features will suffice to characterize an OS as a multi-programmed OS? More than one program may be loaded into main memory at the same time for execution If a program waits for certain events such as I/O, another program is immediately scheduled for execution If ... program is immediately scheduled for execution. (a) (a) and (b) (a) and (c) (a), (b) and (c)
asked Sep 16, 2014 in Operating System Kathleen 4.9k views
24 votes
4 answers
9
Dynamic linking can cause security concerns because Security is dynamic The path for searching dynamic libraries is not known till runtime Linking is insecure Cryptographic procedures are not available for dynamic linking
asked Sep 16, 2014 in Operating System Kathleen 2.8k views
18 votes
1 answer
10
The optimal page replacement algorithm will select the page that Has not been used for the longest time in the past Will not be used for the longest time in the future Has been used least number of times Has been used most number of times
asked Sep 16, 2014 in Operating System Kathleen 2.4k views
21 votes
4 answers
11
Which of the following scheduling algorithms is non-preemptive? Round Robin First-In First-Out Multilevel Queue Scheduling Multilevel Queue Scheduling with Feedback
asked Sep 16, 2014 in Operating System Kathleen 3.2k views
81 votes
10 answers
12
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 both $32$ bits wide. The memory is byte addressable. For virtual to physical address translation, the $10$ most ... access a virtual address is approximately (to the nearest $0.5$ ns) $1.5$ ns $2$ ns $3$ ns $4$ ns
asked Sep 15, 2014 in Operating System gatecse 17.8k views
1 vote
2 answers
13
Page tables are stored in memory , which has access time of 100 ns. The TLB holding 8 page table entries, has an access time of 10 ns. Using execution of process , it is found that 85 % of the time, a required page table entry exist in TLB and only 2 % of ... , assuming page memory access requires 2 memory accesses and TLB requires one memory access. A) 38120 ns B) 40000 ns C) 40120 ns D) None
asked Sep 15, 2014 in Operating System gatecse 1.2k views
1 vote
1 answer
14
Please explain with a situation where bounded waiting is satisfied but progress is not.
asked Sep 15, 2014 in Operating System ABG 538 views
79 votes
7 answers
15
Consider the following code fragment: if (fork() == 0) { a = a + 5; printf("%d, %p n", a, &a); } else { a = a - 5; printf ("%d, %p n", a,& a); } Let $u,v$ be the values printed by the parent process and $x,y$ ... $u = x + 10 \text{ and } v != y$ $u + 10 = x \text{ and } v = y$ $u + 10 = x \text{ and } v != y$
asked Sep 15, 2014 in Operating System Nishant T-rex 13.3k views
32 votes
3 answers
16
Consider a disk with the $100$ tracks numbered from $0$ to $99$ rotating at $3000$ rpm. The number of sectors per track is $100$ and the time to move the head between two successive tracks is $0.2$ millisecond. Consider a set of disk requests to read ... initially at track $0$ and the elevator algorithm is used to schedule disk requests, what is the worse case time to complete all the requests?
asked Sep 15, 2014 in Operating System Kathleen 4.4k views
30 votes
3 answers
17
Two concurrent processes $P1$ and $P2$ want to use resources $R1$ and $R2$ in a mutually exclusive manner. Initially, $R1$ and $R2$ ... to deadlock. Exchange the statements $Q1$ and $Q3$ and statements $Q2$ and $Q4$. Is mutual exclusion guaranteed now? Can deadlock occur?
asked Sep 15, 2014 in Operating System Kathleen 2.4k views
33 votes
3 answers
18
Consider a disk with the following specifications: 20 surfaces, 1000 tracks/surface, 16 sectors/track, data density 1 KB/sector, rotation speed 3000 rpm. The operating system initiates the transfer between the disk and the memory sector-wise. Once the head has been placed on ... transfer? What is the maximum percentage of time the CPU is held up for this disk I/O for cycle-stealing DMA transfer?
asked Sep 15, 2014 in Operating System Kathleen 4.6k views
40 votes
5 answers
19
Consider Peterson's algorithm for mutual exclusion between two concurrent processes i and j. The program executed by process is shown below. repeat flag[i] = true; turn = j; while (P) do no-op; Enter critical section, perform actions, then exit critical section Flag[i] = false; Perform other non- ... turn = i flag[j] = true and turn = j flag[i] = true and turn = j flag[i] = true and turn = i
asked Sep 15, 2014 in Operating System Kathleen 7.3k views
27 votes
3 answers
20
Consider a machine with $64$ MB physical memory and a $32$-bit virtual address space. If the page size s $4$ KB, what is the approximate size of the page table? $\text{16 MB}$ $\text{8 MB}$ $\text{2 MB}$ $\text{24 MB}$
asked Sep 15, 2014 in Operating System Kathleen 12.8k views
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