16 votes 16 votes A given set of processes can be implemented by using only parbegin/parend statement, if the precedence graph of these processes is ______ Operating System gate1991 operating-system normal precedence-graph fill-in-the-blanks + – Kathleen asked Sep 12, 2014 retagged Apr 17, 2021 by Lakshman Bhaiya Kathleen 3.1k views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments set2018 commented Jul 7, 2017 reply Follow Share pls explain the concept of precedence graph @Arjun Sir @Bikram Sir 1 votes 1 votes Bikram commented Jul 7, 2017 i edited by Bikram Jul 8, 2017 reply Follow Share A precedence graph is a directed, acyclic graph whose nodes correspond to individual statements. see the example here http://uclab.khu.ac.kr/lectures/2003_autumn_os/lecture3.pdf also read https://cis.temple.edu/~giorgio/old/cis307s96/readings/precedence.html 8 votes 8 votes amlan97 commented Jan 1, 2021 reply Follow Share is perbrgin /perend is similar with cobegin/coend ? 0 votes 0 votes Please log in or register to add a comment.
Best answer 17 votes 17 votes A given set of processes can be implemented by using only parbegin/parendstatement, if the precedence graph of these processes is properly nested Reference : http://nob.cs.ucdavis.edu/classes/ecs150-2008-04/handouts/sync.pdf It should be closed under par begin and par end. Process execute concurrently. https://gateoverflow.in/1739/gate1998_24#viewbutton In this question precedence graph is nested. All the process execute concurrently, closed under par begin and par end. If you see all the serial execution come then signal the resource and and parallel process down the value (resource ) similar all the process which are which are dependent to other one, other one release the resource then it will be got that with down and after release the its own resource. In the sense all the process are executing concurrently. minal answered Nov 8, 2015 edited Jun 28, 2018 by kenzou minal comment Share Follow See all 9 Comments See all 9 9 Comments reply Arjun commented Nov 8, 2015 reply Follow Share graph is nested means? 2 votes 2 votes minal commented Nov 8, 2015 reply Follow Share 1. it should be closed under par begin and par end ... 2. process execute concurrently .... https://gateoverflow.in/1739/gate1998_24#viewbutton in this question precedence graph is nested .... 1) all the process execute concurrently ..closed under par begin and par end .. 2) if you see all the serial execution come then signal the resource and and parallel process down the value (resource ) similar all the process which are which are dependent to other one , other one release the resource then it will be got that with down ..and after release the its own resource .. in the sense all the process are executing concurrently ... may be my words are not clear to understand .... but moto is clear i think ... 1 votes 1 votes Arjun commented Nov 8, 2015 reply Follow Share yes :) its about that word "nested" 1 votes 1 votes Gate Mm commented Dec 2, 2015 reply Follow Share @Sonam :Please explain the second aspect 2) if you see all the serial execution come then signal the resource and and parallel process down the value (resource ) similar all the process which are which are dependent to other one , other one release the resource then it will be got that with down ..and after release the its own resource .. in the sense all the process are executing concurrently ... 0 votes 0 votes minal commented Dec 2, 2015 reply Follow Share in simple words if some process hold resource then , and that want other ,so process which have resource ,will up and release that and other one down on it and got the resource 3 votes 3 votes rahul sharma 5 commented Dec 10, 2017 reply Follow Share The meaning of nested is not clear from the answer and the link provided:( 1 votes 1 votes rohith1001 commented Jan 4, 2020 i edited by rohith1001 Jan 4, 2020 reply Follow Share I think "properly nested" graphs represent any one of the below: inner loops of begin-end which is enclosed in the outer loop of parbegin-parend inner loops of parbegin-parend which is enclosed in the outer loop of begin-end. (Example of this is the below diagram.) And the question is asking for precedence graph of processes that can be implemented using only parbegin and parend. I think it is different from "properly nested" graphs. The graph expected in the question would be as the below diagram. (I don't know the exact name given for these type of precedence graphs) Reference: https://www.ics.uci.edu/~bic/os/OS/PROOFS/bicc02v2.pdf An important class of process flow graphs are those that are properly nested. Let S(p1,...,pn) denote the serial execution of processes p1 through pn and let P(p1,...,pn) denote the parallel execution of processes p1 through pn. Then a process flow graph is properly nested if it can be described by the functions S and P, and only function composition. 2 votes 2 votes amlan97 commented Jan 1, 2021 reply Follow Share is perbrgin /perend is similar with cobegin/coend ? 0 votes 0 votes Venky8 commented Mar 30, 2021 i edited by Venky8 Mar 30, 2021 reply Follow Share @amlan97 Yes they are the same. co - concurrent, par - parallel. https://cis.temple.edu/~giorgio/old/cis307s96/readings/precedence.html. 1 votes 1 votes Please log in or register to add a comment.