SJF preemptive scheduling

1
votes

I got this table for pre-emptive Shortest Job First

JOB     ARRIVAL Burst
        TIME    Time
A       15      5
B       27      8
C       19      7
D       4       6
E       10      8   
F       52      4
G       33      10
H       38      2

before G, there is 2 seconds before it perform, do i need to include that?

The table given in my answer using gantt chart is 

 D  E  E  A  A  C  C  B  B  H  G     F 
4 10 15 18 19 23 27 30 33 38 40 50 52

my question is, is it ok to include the waiting time before F arrives?

1
operating-systemschedulingjobsjob-schedulingshortest
Care to elaborate? I'm afraid I don't know what you're asking. I believe there is something missing. – John Dvorak
the table is the given my answer using gantt chart is D E E A A C C B B H G F 4 10 15 18 19 23 27 30 33 38 40 50 52 my question is, is it ok to include the waiting time before F arrives? – John Seigfred Manzanares
included where? This site is not a forum specific to your class, your college or your teacher. This site is open to the wide world. We don't have the context you have, and we don't know what is required by your assignment. – John Dvorak
beg with my comment, i cant put it in a table for – John Seigfred Manzanares
Then you should either write an answer, remove the question or at least indicate in the title that the question is resolved. – John Dvorak

1 Answers

1
votes

Given your question,first of all I'd like to mention that you haven't mention that whether processes are evaluated on the basis of time-quantum which seems,but,can't be verified because of answer given in your textbook violating the time quanta concept too.

I doubt why the answer consists of two separate A process,if the given scheduling algorithm is Shortest Job First (SJF).

But,I'd like to write this answer. The Gantt chart for this process' list would be :-

|----|   D   |    E    |  A   |    C   |    B    | H |     G    |----|  F  |

0    4      10        18     23       30        38  40          50  52    56

So, the answer to your question is

"YES, WE WOULD HAVE TO CONSIDER THE TIME_GAP OF 2 UNIT(FROM 50 TO 52), AS THERE WON'T BE ANY PROCESS IN THE READY QUEUE TO GET SCHEDULED AT THAT TIME,AS ALL OTHER PROCESS WOULD HAVE EXECUTED FULLY IN THE GIVEN TIME."