0 votes 0 votes Which of the following transitions are not possible? (Assume resource preemption is not allowed) A) 2 and 4 B) 3 and 5 C)4 and 5 D)3 and 5 if resource preemption is not allowed then answer should be A) but answer given is D) how it is possible? Operating System operating-system process + – reena_kandari asked Sep 29, 2017 reena_kandari 2.2k views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
1 votes 1 votes Irrespective of anything, transitions 3 and 5 are not allowed at all! "Ready to Waiting" and "Waiting to Running" are not possible at all. Manu Thakur answered Sep 29, 2017 Manu Thakur comment Share Follow See all 8 Comments See all 8 8 Comments reply reena_kandari commented Sep 29, 2017 reply Follow Share what if a process need first I/O and then CPU burst, then transition 3 is allowed, correct? 0 votes 0 votes joshi_nitish commented Sep 29, 2017 reply Follow Share transition 3 is never allowed. for your case "what if a process need first I/O and then CPU burst", the process will be transferred from new state to I/O... PS: process will be send to ready queue only if it needs CPU next. 0 votes 0 votes reena_kandari commented Sep 29, 2017 reply Follow Share Okay, But 2 is also not allowed in non-preemptive scheduling. 0 votes 0 votes Manu Thakur commented Sep 29, 2017 reply Follow Share it seems you didn't read properly from Galvin. Execution time will always start with CPU burst and End with CPU Burst. without running a process on CPU how will system come to know that a process needs I/O ? 3 votes 3 votes reena_kandari commented Sep 30, 2017 reply Follow Share yes you are correct @manu. thanks for correcting. 0 votes 0 votes rio commented Dec 3, 2017 reply Follow Share @manu thakur sir i think this question is wrongly framed because see the edge edge number 3 is never possible edge number 5 is only possible in uni processor and non multi programming system but as ready queue is present so it a multi programming system. question says resource(cpu) preemption not allowed so clearly edge 2 must not be present . 0 votes 0 votes HeadShot commented Jan 14, 2018 reply Follow Share Yes 5th one is not possible. But sometimes at the time of resource pre-emption process may switch from ready queue to block queue. So 3rd one is possible. But as it is mentioned in the question that resource pre-emption is not allowed , option D is correct. 0 votes 0 votes HeadShot commented Jan 14, 2018 reply Follow Share May be this will help. 0 votes 0 votes Please log in or register to add a comment.