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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 tC CPU milliseconds and then initiates a single I/O operation that lasts for tio milliseconds. It is assumed that the computer where the processes execute has sufficient number of I/O devices and the OS of the computer assigns different 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 I/O operation is ___________.
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- 10
- 100
- 1000
- 500
Correct Option: C
The Gantt chart for Round robin algorithm for the first iteration execution for each of the 3 processes is as follows : 
After finishing tc CPU ms at time 500ms, C goes for I/O operation, that needs 500ms more, so the time at which process C would complete its first I/O operations is 500 + 500 = 1000 ms
