define Shortest-Job-First (SJF) Scheduling ?, Basic Computer Science


• It is also known as Shortest-Process-Next (SPN).
• Shortest-Job-First (SJF) is a non-preemptive order in which waiting job (or process) with the smallest predictable run-time-to-completion is run next. In other language, when CPU is available, it is allotted to the process that has smallest next CPU burst.
• The SJF scheduling is mainly suitable for batch jobs for which the run times are known in advance. Since the SJF scheduling algorithm gives the minimum average time for a given set of processes, it is almost certainly optimal.
• The SJF algorithm helps short jobs (or processors) at the cost of longer ones.
• The understandable problem with SJF scheme is that it requires precise acquaintance of how long a job or process will run, and this information is not generally available.
• In the production environment where the same jobs run frequently, it may be possible to provide reasonable estimate of run time, based on the past presentation of the process. But in the development environment users not often know how their program will execute.
• The best SJF algorithm can do is to rely on user approximation of run times.
• Like FCFS, SJF is non preemptive therefore, it is not helpful in timesharing environment in which reasonable answer time must be sure.
Posted Date: 5/2/2012 8:34:44 AM | Location : United States







Related Discussions:- define Shortest-Job-First (SJF) Scheduling ?, Assignment Help, Ask Question on define Shortest-Job-First (SJF) Scheduling ?, Get Answer, Expert's Help, define Shortest-Job-First (SJF) Scheduling ? Discussions

Write discussion on define Shortest-Job-First (SJF) Scheduling ?
Your posts are moderated
Related Questions
origin,nature and impact of operation research

Define Levels of Abstraction in a DBMS, explain briefly, Conceptual Schema, Physical Schema, External Schema

what is meant by deliverable in strus base applications

To find the minimum number of shelves in the loading process in cars

Question 1 What are the various steps involved in pre-production design? Question 2 What are the different kinds of perspectives used in a layout? Question 3 Descr

1. What actions need to be taken when a program terminates or a process is killed? What if that process destruction is not the consequence of normal termination, but rather is the

EXPLAIN CAI? AND ITS PITFALLS

Question 1 What are the different kinds of editing? Explain them in detail Question 2 Write a long note on the viewfinder of a camera Question 3 Describe the various typ

COMMUNICATION CHANNELS: A wire pair connecting two telephones is the simplest circuit, allowing communication in both directions. Other channels include coaxial cables, optica

#whatis cai?and its pit fallsquestion..