Practical stuff for Exam

Question 1

2 Scheduling Pre-emptive Algorithm:

Answer 1

Round Robin(RR)
Smallest remaining time first (SRTF)

Question 2

2 Scheduling Non-Pre-emptive Algorithm:

and what does non-preemptive mean?

Answer 2

FCFS
SJN(SPN)

Once the process gets scheduled, it will run till the completion

Question 3

Waiting time formula?

Answer 3

WT=Ts - Ta

start time - arrival time

Question 4

Turnaround time formula?

Answer 4

TT=WT + B (burst time)

B=end time -start time

TT= finish time - AT

Question 5

Response time formula?

Answer 5

RT=start time(Ts) - process start time(T0)

Question 6

Response ratio formula?

Answer 6

TT/B

Turnaround time /Burst time

Question 7

How to plot ‘X’ in FCFS table?

Answer 7

1) Sort Process table by arrival time
2) Plot arrival time using ->
3) Plot ‘X’ from start of burst time till finish
4) if same priority level then choose with earliest AT

Question 8

How to plot ‘X’ in SPN table

Answer 8

1) Sort Process table by burst time
2) plot ax with arriavl time O
3) do process which has shortest bT just look at sorted table
4) If longer process but higher priority do higher priority one

Question 9

How to plot ‘X’ in RR table

Answer 9

Round Robin- each process is an given an equal time slice

1) Sort Process table by arrival time
2) Plot arrival time using ->
3) you can only put ‘X’ as many times as quantum/time slice
4) if ‘X’ plotted and no other process has arrived then plot again
5) follow order in process table

Question 10

How to plot ‘X’ in SRTF table

Answer 10

No queue

1) Sort Process table by arrival time

Question 11

Cache: calculate Fault Ratio(FR)

Answer 11

FR = Fault/(Fault + Hit)

change answer to %

Question 12

Cache: calculate Hit Ratio(HR)

Answer 12

HR= Hit/(Fault + Hit)

Or

1 - FR

Question 13

How to compare algorithms?

Answer 13

Choose the one closest to Optimum
Best Cases:
Highest HR
Lowest FR

Question 14

How to solve Banker’s Algorithm

Answer 14

need = max/claim - allocation

Then do avaliable +allocation