11,077 views
11 votes
11 votes

Suppose two jobs, each of which needs $10$ minutes of CPU time, start simultaneously. Assume $50\%$ I/O wait time. How long will it take for both to complete, if they run sequentially?

  1. 10
  2. 20
  3. 30
  4. 40

10 Answers

2 votes
2 votes
option c .
Total time of one process=cpu time + I/O time=10+5=15
Since they are executing sequencially. So total time 15+15=30
0 votes
0 votes

here two jobs run sequentially...so second job complete after completion of first job...

let time taken by first job to complete execution=x..but here job remains in i/o 50% time...means it will remain in cpu only 50% time...now we have cpu time=10 min

or i can say 50% of x=10 min..,so time taken by first job to complete execution=20 min,similarly second job will also take 20 min

so total time should be 40 min......optionD..

0 votes
0 votes
its 30
0 votes
0 votes

CPU time is 10 minutes (given).

I/O time is 50% of the total time means total time is 20 minutes (10 minutes CPU time, 10 minutes I/O time).

Now for one process total time is 20 minutes. for two processes total time is:-

case 1: if they run Sequentially then overlapping is not allowed and total time is 40 minutes

case 2: if overlapping is allowed (Parallel processing) then I/O time of P1 can be overlapped with CPU time of P2. In this case the total time will be 30 minutes

edited by
Answer:

Related questions

13 votes
13 votes
2 answers
1
go_editor asked Jun 19, 2016
10,024 views
Suppose a system contains $n$ processes and system uses the round-robin algorithm for CPU scheduling then which data structure is best suited ready queue of the processst...
7 votes
7 votes
2 answers
2
go_editor asked Jun 19, 2016
3,820 views
Consider the following program.main() { fork(); fork(); fork(); }How many new processes will be created?8675
12 votes
12 votes
4 answers
3
go_editor asked Jun 17, 2016
3,823 views
In a lottery scheduler with 40 tickets, how we will distribute the tickets among 4 processes $P_1, P_2, P_3$ and $P_4$ such that each process gets 10%, 5%, 60% and 25% re...
6 votes
6 votes
2 answers
4
go_editor asked Jun 17, 2016
10,798 views
If there are 32 segments, each size 1 k bytes, then the logical address should have13 bits14 bits15 bits16 bits