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(also First Come, First Served)

FCFS definition

FCFS is a scheduling algorithm that helps operating systems and networks efficiently and automatically carry out tasks, processes, and requests in the order in which they are added to the queue. FCFS scheduling is also known as first-in, first-out (FIFO) or first-come, first-choice (FCFC) scheduling. FCFS algorithms perform tasks and requests predictably due to their simplicity. FCFS algorithms are an emulation of real-world customer service situations. Because it doesn’t waste time ranking tasks and requests by their priority or amount of complexity, FCFS is among the most productive and autonomous types of scheduling algorithm.

Examples of FCFS scheduling:

  • Buying a movie ticket at the counter. This algorithm serves people in the queue order. The first person in line buys a ticket, then the next person, and so on. This process will continue until the last person in line has purchased a ticket. This method mimics the CPU process.

Advantages of FCFS:

  • Simplicity. Orders are fulfilled in order, simplifying scheduling and process. Orders are simply performed in chronological sequence.
  • User friendly. Order scheduling and code writing are straightforward for team members. Easy scheduling saves time and labor. It’s a foolproof technique that also reduces errors.
  • Easy to implement. FCFS’s simplicity makes it easier to integrate into existing systems. FCFS order scheduling can be deployed quickly and inexpensively into any scheduling system your company uses. FCFS can be used soon after its implementation.

Limitation of FCFS:

  • Long waiting time. FCFS processes orders in order since it is non-preemptive. This means a business order can start processing once the previous order has been completed. A CPU-allocated process will never release it until it finishes. If the initial order has a long burst time, orders following it must wait for fulfillment, regardless of their burst times.
  • Lower device usage. Simple FCFS is inefficient. Longer wait periods accompany this. If the CPU is busy processing a long order, all other orders lie idle, causing a backup. FCFS is particularly wasteful because the CPU can only process one order at a time.
  • CPU over I/O. FCFS emphasizes CPU over I/O. The algorithm is more CPU friendly than I/O friendly. This may dissuade I/O system users.

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