Queue Discipline – UGCNET17

Unit VIII: Business Statistics and Operations Management

Queue Discipline	Description	Advantages	Disadvantages
First-Come, First-Served (FCFS)	Serves customers in the order they arrive.	Simple, fair for most scenarios.	Can cause long delays if service times vary greatly.
Last-Come, First-Served (LCFS)	Serves the most recent arrival first.	Quick service for the most recent arrivals.	Unfair to customers who have waited longer.
Priority Queueing	Customers are served based on priority levels.	Ensures urgent or high-priority customers are served first.	Low-priority customers may experience delays (starvation).
Shortest Job First (SJF)	Serves customers with the shortest service time first.	Minimizes average waiting time.	Can lead to starvation for long tasks.
Round Robin (RR)	Customers are served in fixed time slices.	Fair distribution of resources.	Can be inefficient if time slices are too small or too large.
Shortest Remaining Processing Time (SRPT)	Serves customers with the least remaining service time.	Minimizes total waiting time.	Can cause starvation for long tasks.
Fair Queueing	Resources are allocated equally among all customers.	Fair allocation of resources.	May not be the most efficient for tasks with different priorities.
Preemptive Queueing	Higher-priority customers can preempt lower-priority ones.	Ensures high-priority tasks are prioritized.	May lead to frequent interruptions or context switching.
Non-Preemptive Queueing	No preemption; once a customer starts service, they are not interrupted.	Simpler, fairer for non-interruptive scenarios.	Can result in delays for other tasks waiting for service.