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$$\scriptsize{\overset{{\large{\textbf{Mark Distribution in Previous GATE}}}}{\begin{array}{|c|c|c|c|c|c|c|c|}\hline \textbf{Year}&\textbf{2021-1}&\textbf{2021-2}&\textbf{2020}&\textbf{2019}&\textbf{2018}&\textbf{2017-1}&\textbf{2017-2}&\textbf{2016-1}&\textbf{2016-2}&\textbf{Minimum}&\textbf{Average}&\textbf{Maximum} \\\hline\textbf{1 Mark Count}&4&2&2&2&3&2&2&1&1&1&2.1&4 \\\hline\textbf{2 Marks Count}&1&3&4&4&3&2&2&4&3&1&2.8&4 \\\hline\textbf{Total Marks}&6&8&10&10&9&6&6&9&7&\bf{6}&\bf{7.8}&\bf{10}\\\hline \end{array}}}$$

# Recent questions in Operating System

1 vote
1
Which of the following statement(s) is/are correct in the context of $\text{CPU}$ scheduling? Turnaround time includes waiting time The goal is to only maximize $\text{CPU}$ utilization and minimize throughput Round-robin policy can be used even when the $\text{CPU}$ time required by each of the processes is not known apriori Implementing preemptive scheduling needs hardware support
1 vote
2
Consider the following multi-threaded code segment (in a mix of C and pseudo-code), invoked by two processes $P_1$ and $P_2$, and each of the processes spawns two threads $T_1$ and $T_2$: int x = 0; // global Lock L1; // global main () { create a thread to execute foo() ... will print the value of $y$ as $2.$ Both $T_1$ and $T_2$, in both the processes, will print the value of $y$ as $1.$
3
Consider a computer system with multiple shared resource types, with one instance per resource type. Each instance can be owned by only one process at a time. Owning and freeing of resources are done by holding a global lock $(L)$. The following scheme ... deadlocks will not occur The scheme may lead to live-lock The scheme may lead to starvation The scheme violates the mutual exclusion property
4
Consider a three-level page table to translate a $39-$bit virtual address to a physical address as shown below: The page size is $\text{4 KB} \;(1\text{KB}=2^{10}$ bytes$)$ and page table entry size at every level is $8$ bytes. A process $P$ is currently ... $2\text{GB}$ of physical memory. The minimum amount of memory required for the page table of $P$ across all levels is _________ $\text{KB}$.
5
In the context of operating systems, which of the following statements is/are correct with respect to paging? Paging helps solve the issue of external fragmentation Page size has no impact on internal fragmentation Paging incurs memory overheads Multi-level paging is necessary to support pages of different sizes
6
Which of the following standard $C$ library functions will always invoke a system call when executed from a single-threaded process in a $\text{UNIX/Linux}$ operating system? $\textsf{exit}$ $\textsf{malloc}$ $\textsf{sleep}$ $\textsf{strlen}$
1 vote
7
Consider a linear list based directory implementation in a file system. Each directory is a list of nodes, where each node contains the file name along with the file metadata, such as the list of pointers to the data blocks. Consider a given directory $\textsf{foo}$. Which of ... file from $\textsf{foo}$ Renaming of an existing file in $\textsf{foo}$ Opening of an existing file in $\textsf{foo}$
1 vote
8
Three processes arrive at time zero with $\text{CPU}$ bursts of $16,\;20$ and $10$ milliseconds. If the scheduler has prior knowledge about the length of the $\text{CPU}$ bursts, the minimum achievable average waiting time for these three processes in a non-preemptive scheduler (rounded to nearest integer) is _____________ milliseconds.
9
Consider the following pseudocode, where $\textsf{S}$ is a semaphore initialized to $5$ in line $\#2$ and $\textsf{counter}$ is a shared variable initialized to $0$ in line $\#1$. Assume that the increment operation in line $\#7$ is $\textit{not}$ ... $0$ after all the threads successfully complete the execution of $\textsf{parop}$ There is a deadlock involving all the threads
10
Consider a hypothetical machine with $3$ pages of physical memory, $5$ pages of virtual memory, and $<A, B, C, D, A, B, E, A, B, C, D, E, B, A, B>$ as the stream of page reference by an application. If $P$ and $Q$ are the number of page faults that the application ... respectively, then $(P,Q)=$ _______(Assuming enough space for storing $3$ page frames) $(11,10)$ $(12,11)$ $(10,11)$ $(11,12)$
11
Consider a disk system having $60$ cylinders. Disk requests are received by a disk drive for cylinders $10,22,20,2,40,6$ and $38$, in that order. Assuming the disk head is currently at cylinder $20$, what is the time taken to satisfy all the ... cylinder to adjacent one and Shortest Seek Time First (SSTF) algorithm is used? $240$ milliseconds $96$ milliseconds $120$ milliseconds $112$ milliseconds
12
Suppose you have a Linux file system where the block size is $2K$ bytes, a disk address is $32$ bits, and an $i-$node contains the disk addresses of the first $12$ direct blocks of file, a single indirect block and a double indirect block. Approximately, what is the largest file that can be represented by an $i-$node? $513$ Kbytes $513$ MBytes $537$ Mbytes $537$ KBytes
13
Consider a single-level page table system, with the page table stored in the memory. If the hit rate to TLB is $80\%$, and it takes $15$ nanoseconds to search the $TLB$, and $150$ nanoseconds to access the main memory, then what is the effective memory access time, in nanoseconds? $185$ $195$ $205$ $175$
14
Match $\text{List I}$ with $\text{List II}$ ... C-III, D-IVA-II, B-IV, C-III, D-IA-II, B-IV, C-I, D-IIIA-IV, B-III, C-II, D-I$Match$
1 vote
15
Assuming that the system call $\text{fork}()$ never fails, consider the following C program $P1$ and $P2$ ... Both Statement $I$ and Statement $II$ are false Statement $I$ is correct but Statement $II$ is false Statement $I$ is incorrect but Statement $II$ is true
16
Comprehension: For the question given below: concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. If $T$ is the capacity of a track in bytes, and $S$ is the capacity of each surface in ... $(T,S)=$ _______ $(50 K, 50000 K)$ $(25 K, 25000 K)$ $(25 K, 50000 K)$ $(40 K, 36000 K)$
17
Comprehension: For the question given below: concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. What is the capacity of the disk, in bytes? $25,000 K$ $500,000 K$ $250,000 K$ $50,000 K$
Comprehension: For the question given below: concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. Given below are two statements: Statement $I$: The ... $II$ are false Statement $I$ is correct but Statement $II$ is false Statement $I$ is incorrect but Statement $II$ is true
Comprehension: For the question given below, concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. If the disk platters rotate at $5400$ rpm ( ... minute), then approximately what is the maximum rotational delay? $0.011$ seconds $0.11$ seconds $0.0011$ seconds $1.1$ seconds
For the question given below, concern a disk with a sector size of $512$ bytes, $2000$ tracks per surface, $50$ sectors per track, five double-sided platters, and average seek time of $10$ milliseconds. If one track of data can be transferred per revolution, then what is the data transfer rate? $2,850$ KBytes/second $4,500$ KBytes/second $5,700$ KBytes/second $2,250$ KBytes/second