1
GATE CSE 2016 Set 2
Numerical
+2
-0
Consider the following processes, with the arrival time and the length of the CPU burst given in milliseconds. The scheduling algorithm used is preemptive shortest remaining-time first.

Process Arrival Time Burst Time
P1
P2
P3
P4
0
3
7
8
10
6
1
3

The average turn around time of these processes is milliseconds.

2
GATE CSE 2015 Set 3
+2
-0.6
For the processes listed in the following table, which of the following scheduling schemes will give the lowest average turnaround time?

Process Arrival Time Processing Time
A 0 3
B 1 6
D 4 4
E 6 2

A
First Come First Serve
B
Non-preemptive Shortest Job First
C
Shortest Remaining Time
D
Round Robin with Quantum value two
3
GATE CSE 2015 Set 1
Numerical
+2
-0
Consider a uniprocessor system executing three tasks T1, T2 and T3, each of which is composed of an infinite sequence of jobs (or instances) which arrive periodically at intervals of 3, 7 and 20 milliseconds, respectively. The priority of each task is the inverse of its period, and the available tasks are scheduled in order of priority, with the highest priority task scheduled first. Each instance of T1, T2 and T3 requires an execution time of 1, 2 and 4 milliseconds, respectively. Given that all tasks initially arrive at the beginning of the 1st millisecond and task preemptions are allowed, the first instance of T3 completes its execution at the end of _____________ milliseconds.
4
GATE CSE 2014 Set 2
Numerical
+2
-0
Three processes $$A, B$$ and $$C$$ each execute a loop of $$100$$ iterations. In each iteration of the loop, a process performs a single computation that requires $${t_c}\,\,CPU$$ milliseconds and then initiates a single $${\rm I}/O$$ operation that lasts for $${t_{io}}$$ milliseconds. It is assumed that the computer where the processes execute has sufficient number of $${\rm I}/O$$ devices and the $$OS$$ of the computer assigns different $${\rm I}/O$$ devices to each process. Also, the scheduling overhead of the $$OS$$ is negligible. The processes have the following characteristics:
Process id tc tio
A 100 ms 500 ms
B 350 ms 500 ms
C 200 ms 500 ms

The processes $$A, B,$$ and $$C$$ are started at times $$0, 5$$ and $$10$$ milliseconds respectively, in a pure time sharing system (round robin scheduling) that uses a time slice of $$50$$ milliseconds. The time in milliseconds at which process $$C$$ would complete its first $${\rm I}/O$$ operation is __________.