Answer:
a) CPU utilization for uniprogramming system = 18.2%
b) CPU utilization for multiprogramming system = 41.379%
Explanation:
IO time = total time – CPU time
For JOB 1
CPU time = 3ms ,
total time= 23ms
IO time = 23-3 = 20ms ,
For JOB 2
CPU time =5ms
total = 29ms
IO time = 29-5 = 24ms
For JOB 3
CPU time = 4ms
total = 14ms
IO time = 14-10 =10ms
1.) In uniprogramming system, operations are performed sequentially
CPU utilization=total CPU time / total real time
CPU utilization =(3+5+4) / (23+29+14)
CPU utilization =0.182 or 18.2%
2) In multiprogramming system, jobs wait for the CPU to get free while performing IO operations concurrently
steps followed by the os
1. IO for 1st job at 0ms
2. IO for 2nd job at 0ms
3. IO for 3rd job at 0ms
4. CPU time for 3rd job at 5ms
5. Next IO job for 3rd job at 9ms END at 14ms
6. CPU time for 1st job at 9ms
7. Next IO job for 1st job at 14ms END at 23ms
8. CPU time for 2nd job at 14ms
9. Next IO job for 2nd job at 15ms END at 29ms
CPU time is 3+5+4 =12ms
Total execution time = 29ms
CPU utilization = 12*100/29= 41.379%
