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

$$\scriptsize{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline
\textbf{Year}& \textbf{2022} & \textbf{2021-1}&\textbf{2021-2}&\textbf{2020}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum}
\\\hline\textbf{1 Mark Count} & 2 &4&2&2&2&3&2&2&1&1&1&2.1&4
\\\hline\textbf{2 Marks Count} & 4 &1&3&4&4&3&2&2&4&3&1&3&4
\\\hline\textbf{Total Marks} & 10 &6&8&10&10&9&6&6&9&7&\bf{6}&\bf{8.1}&\bf{10}\\\hline
\end{array}}}$$

Previous GATE Questions in Operating System

39 votes

4 answers

261

GATE CSE 2006 | Question: 06, ISRO2009-14
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. $1$ $2$ $3$ $4$

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 nee...

16.0k views

Rucha Shelke asked Sep 16, 2014

20 votes

3 answers

262

GATE CSE 2002 | Question: 20
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() { ... immediately after $c1$ and immediately before $c2$ so that the program works correctly for multiple producers and consumers.

The following solution to the single producer single consumer problem uses semaphores for synchronization.#define BUFFSIZE 100 buffer buf[BUFFSIZE]; int first = last = 0;...

6.3k views

Kathleen asked Sep 15, 2014

37 votes

3 answers

263

GATE CSE 2002 | Question: 19
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 ... that can be contained in each page? How many bits are available for storing protection and other information in each page table entry?

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...

14.4k views

Kathleen asked Sep 15, 2014

16 votes

2 answers

264

GATE CSE 2002 | Question: 18-a
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.

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 term...

6.3k views

Kathleen asked Sep 15, 2014

31 votes

6 answers

265

GATE CSE 2002 | Question: 2.22
In the index allocation scheme of blocks to a file, the maximum possible size of the file depends on the size of the blocks, and the size of the address of the blocks. the number of blocks used for the index, and the size of the blocks. the size of the blocks, the number of blocks used for the index, and the size of the address of the blocks. None of the above

In the index allocation scheme of blocks to a file, the maximum possible size of the file depends onthe size of the blocks, and the size of the address of the blocks.the ...

14.7k views

Kathleen asked Sep 15, 2014

44 votes

5 answers

266

GATE CSE 2002 | Question: 2.21
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 ... is immediately scheduled for execution. (a) (a) and (b) (a) and (c) (a), (b) and (c)

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 t...

12.8k views

Kathleen asked Sep 15, 2014

28 votes

4 answers

267

GATE CSE 2002 | Question: 2.20
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

Dynamic linking can cause security concerns becauseSecurity is dynamicThe path for searching dynamic libraries is not known till runtimeLinking is insecureCryptographic p...

6.9k views

Kathleen asked Sep 15, 2014

21 votes

1 answer

268

GATE CSE 2002 | Question: 1.23
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

The optimal page replacement algorithm will select the page thatHas not been used for the longest time in the pastWill not be used for the longest time in the futureHas b...

8.3k views

Kathleen asked Sep 15, 2014

31 votes

5 answers

269

GATE CSE 2002 | Question: 1.22
Which of the following scheduling algorithms is non-preemptive? Round Robin First-In First-Out Multilevel Queue Scheduling Multilevel Queue Scheduling with Feedback

Which of the following scheduling algorithms is non-preemptive?Round RobinFirst-In First-OutMultilevel Queue SchedulingMultilevel Queue Scheduling with Feedback

18.3k views

Kathleen asked Sep 15, 2014

121 votes

15 answers

270

GATE CSE 2003 | Question: 78
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 ... virtual address is approximately (to the nearest $0.5$ ns) $1.5$ ns $2$ ns $3$ ns $4$ ns

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 addres...

50.2k views

gatecse asked Sep 15, 2014

123 votes

9 answers

271

GATE CSE 2005 | Question: 72
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 $x,y$ be the values printed by the child ... $u + 10 = x \text{ and } v = y$ $u + 10 = x \text{ and } v != y$

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 pr...

37.6k views

Nishant T-rex asked Sep 14, 2014

40 votes

3 answers

272

GATE CSE 2001 | Question: 20
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 ... at track $0$ and the elevator algorithm is used to schedule disk requests, what is the worse case time to complete all the requests?

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...

11.0k views

Kathleen asked Sep 14, 2014

35 votes

3 answers

273

GATE CSE 2001 | Question: 19
Two concurrent processes $P1$ and $P2$ want to use resources $R1$ and $R2$ in a mutually exclusive manner. Initially, $R1$ and $R2$ ... . Exchange the statements $Q1$ and $Q3$ and statements $Q2$ and $Q4$. Is mutual exclusion guaranteed now? Can deadlock occur?

Two concurrent processes $P1$ and $P2$ want to use resources $R1$ and $R2$ in a mutually exclusive manner. Initially, $R1$ and $R2$ are free. The programs executed by the...

5.6k views

Kathleen asked Sep 14, 2014

44 votes

3 answers

274

GATE CSE 2001 | Question: 8
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 ... What is the maximum percentage of time the CPU is held up for this disk I/O for cycle-stealing DMA transfer?

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 sy...

10.2k views

Kathleen asked Sep 14, 2014

59 votes

5 answers

275

GATE CSE 2001 | Question: 2.22
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] = ... i flag[j] = true and turn = j flag[i] = true and turn = j flag[i] = true and turn = i

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 = ...

27.2k views

Kathleen asked Sep 14, 2014

49 votes

4 answers

276

GATE CSE 2001 | Question: 2.21
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? $\text{16 MB}$ $\text{8 MB}$ $\text{2 MB}$ $\text{24 MB}$

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 ...

66.9k views

Kathleen asked Sep 14, 2014

59 votes

4 answers

277

GATE CSE 2001 | Question: 2.20
Which of the following does not interrupt a running process? A device Timer Scheduler process Power failure

Which of the following does not interrupt a running process?A deviceTimerScheduler processPower failure

24.7k views

Kathleen asked Sep 14, 2014

25 votes

2 answers

278

GATE CSE 2001 | Question: 1.22
Which of the following requires a device driver? Register Cache Main memory Disk

Which of the following requires a device driver?RegisterCacheMain memoryDisk

10.6k views

Kathleen asked Sep 14, 2014

22 votes

2 answers

279

GATE CSE 2001 | Question: 1.21
Consider a virtual memory system with FIFO page replacement policy. For an arbitrary page access pattern, increasing the number of page frames in main memory will always decrease the number of page faults always increase the number of page faults sometimes increase the number of page faults never affect the number of page faults

Consider a virtual memory system with FIFO page replacement policy. For an arbitrary page access pattern, increasing the number of page frames in main memory willalways d...

8.2k views

Kathleen asked Sep 14, 2014

37 votes

3 answers

280

GATE CSE 2001 | Question: 1.20
Where does the swap space reside? RAM Disk ROM On-chip cache

Where does the swap space reside?RAMDiskROMOn-chip cache

12.8k views

Kathleen asked Sep 14, 2014

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