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

# Recent questions in Operating System

1 vote
1
In a particular system it is observed that, the cache performance gets improved as a result of increasing the block size of the cache. The primary reason behind this is : Programs exhibits temporal locality Programs have small working set Read operation is frequently required rather than write operation Programs exhibits spatial locality
1 vote
2
Starvation can be avoided by which of the following statements: By using shortest job first resource allocation policy . By using first come first serve resources allocation policy. (i) only (i) and (ii) only (ii) only None of the options
1 vote
3
Page fault frequency in an operating system is reduced when the : Process tend to be I/O bound Locality of reference is applicable to the process Size of pages is reduced Processes tend to be CPU bound
1 vote
4
When we move from the outermost track to the innermost track in a magnetic disk, then density(bits per linear inch) increases. decreases. remains the same. either remains constant or decreases.
5
The file structure that redefines its first record at a base of zero uses the term relative organization. key fielding. dynamic reallocation. all of these.
6
What is the elapsed time of $P$ if records of $F$ are organized using a blocking factor of $2$(i.e. each block on $D$ contains two records of $F$) and $P$ uses one buffer? $12$ sec. $14$ sec. $17$ sec. $21$ sec.
7
A long-term monitor should show any immediate performance problems should show I/O, paging and processor activity need show only the I/O and processor activity usually reports only on terminal displays
8
Determine the number of page faults when references to pages occur in the following order: $1,2,4,5,2,1,2,4$. Assume that the main memory can accommodate $3$ pages and the main memory already has the pages $1$ and $2$, with page $1$ having been brought earlier than page $2$.(LRU algorithm is used). $3$ $5$ $4$ None of these.
9
Working set$(t,k)$ at an instant of time, $t$,is The set of $k$ future references that the operating system will make The set of future references that the operating system will make in the next $'k'$ time units The set of $k$ references with high frequency The set of pages that have been referenced in the last $k$ time units
10
The Banker's algorithm is used: to rectify deadlock. to prevent deadlock. to detect deadlock. to detect and solve deadlock.
1 vote
11
Which of the following statements about semaphores is true? $P$ and $V$ operations should be indivisible operations. A semaphore implementation should guarantee that threads do not suffer indefinite postponement. If several threads attempt a $P(S)$ operation simultaneously, only one thread should be allowed to proceed. All of the above.
1 vote
12
Copying a process from memory to disk to allow space for other processes is called: Swapping Demand Paging Deadlock Page Fault
13
The degree of multi programming is controlled by: CPU Scheduler Long-term Scheduler Context Switching Medium term Scheduler
14
The principle of locality of reference justifies the use of Non reusable Cache memory Virtual memory None of the above
15
In which one of the following pages replacement policies, Belady's anomaly may occur? FIFO LRU Optimal MRU
16
A process that is based on IPC mechanism which executes on different systems and can communicate with other processes using message based communication is called _______. Local Procedure Call Remote Procedure Call Inter Process Communication Remote Machine Invocation
17
Consider a system with $m$ resources of same type being shared by $n$ processes. Resources can be requested and released by processes only one at a time. The system is deadlock free if and only if The sum of all max needs is $< m+n$ The sum of all max needs is $>m+n$ Both of above None
Consider three processes (process id $0,1,2$ respectively) with compute time bursts $2,4$ and $8$ time units. All processes arrive at time zero. Consider the Longest Remaining Time First (LRTF) scheduling algorithm. In LRTF ties are broken by giving priority to the process with the lowest process id. The average turn around time is $13$ units $14$ units $15$ units $16$ units
Consider three processes, all arriving at time zero, with total execution time of $10,20$ and $30$ units, respectively. Each process spends the first $20\%$ of execution time doing I/O, the next $70\%$ of time doing computation, and the last $10\%$ of time doing I/O again. The ... as much as possible. For what percentage of time does the CPU remain idle? $0\%$ $10.6\%$ $30.0\%$ $89.4\%$
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. $1$ $2$ $3$ $4$