OPERATING SYSTEM

  

1. On a single-processor system, explain the benefit the better performance of multi-threaded kernel threads over single threaded kernel threads

2. But not parallelism, it is achievable to have concurrency in operating system threading?

3. The following processes are being scheduled using a priority (a smaller priority number implies a higher priority) and shortest job first all preemptive scheduling algorithms.

Process Priority   Burst   Arrival

P1  50   30  0

P2  40  35  25

P3  40  35  30

P4  45  25  60

P5  15  20  100

P6  20  20  105

i. Draw the Gantt charts that illustrate the execution of these processes using the above scheduling algorithms.

ii. What is the turnaround time of each process for each of the scheduling algorithms in part a?

iii. What is the waiting time of each process for each of these scheduling algorithms?

Which of the algorithms results in the minimum average waiting time (over all processes)? 

  

1. Consider a logical address of 128 pages of 1024 words each, mapped onto a physical memory of 64 frames.

i. How many bits are there in the logical address?

ii. How many bits are there in the physical address?

iii. What is the size of the page table?