Describe Priority Scheduling algorithm of operating system?, Basic Computer Science

Priority Scheduling

• The fundamental idea is straightforward: each process is assigned a priority, and priority is permitted to run. Equal-Priority processes are scheduled in FCFS order. The shortest-Job-First (SJF) algorithm is a special case of general priority scheduling algorithm.
• Priority can be defined either internally or outwardly. Internally distinct priorities use some measurable quantities or behaviors to compute priority of a process.
• An SJF algorithm is simply a priority algorithm where the priority is the inverse of the (predicted) next CPU burst. That is, the longer the CPU explodes, the lower the priority and vice versa.
Illustrations of Internal priorities are
• Deadlines.
• Memory necessities.
• CPU Vs I/O necessities.
• File necessities,
for example, number of open files.
Externally distinct priorities are set by criteria that are external to operating system for example:
• The significance of process.
• Kind or amount of funds being rewarded for computer use.
• The division sponsoring the work.
• A preemptive priority algorithm will preemptive the CPU if the priority of the newly arrival process is higher than the priority of the currently running process.
• This scheduling can be either preemptive or non preemptive
• A non-preemptive priority algorithm will simply put the new process at the head of the ready queue.
A major trouble with priority scheduling is indefinite blocking or starvation. A solution to the trouble of indefinite blockage of the low-priority process is aging. Aging is a method of gradually increasing the priority of processes that wait in the system for an extended period of time.
Posted Date: 5/2/2012 8:39:06 AM | Location : United States







Related Discussions:- Describe Priority Scheduling algorithm of operating system?, Assignment Help, Ask Question on Describe Priority Scheduling algorithm of operating system?, Get Answer, Expert's Help, Describe Priority Scheduling algorithm of operating system? Discussions

Write discussion on Describe Priority Scheduling algorithm of operating system?
Your posts are moderated
Related Questions
MAGNETIC CORE MEMORY: This type of memory is used extensively in airborne digital systems, although integrated circuits are being developed with most modern aircraft systems.

Question 1 Define virtualization. Discuss the benefits of virtualization. Discuss the benefits of server virtualization Question 2 What is para virtualization? How para vi

Consider the one-time pad encryption scheme to encrypt a 1-bit message m, and assume m is chosen with uniform distribution from message space M={0,1}. Let E1 be the event "message

The easiest way to approach pipelining is to regard as the three stage fetch, decode and execute instruction execution cycle outlined earlier. There are times during each of these

Question 1 Write down the Booth's Multiplication Algorithm. Justify the Booth's Multiplication Algorithm Question 2 Explain the functions of ALU Question 3 Define the term ins

IP provide connectionless service to upper layer IP protocol is very simple could not guarantee the reliability of transportations IP protocol is Point to Point IP provide the unif

board coloring


ATM Theory - Unspecified Bit Rate Is intended for non-real time applications, that is, those not requiring tightly constrained delay and delay variation. Examples of applications