First Come, First Served – FCFS Meaning?

FCFS meaning

FCFS meaning – First Come, First Served (FCFS) is a scheduling technique used by networks and operating systems to effectively and automatically carry out queued activities, processes, and requests in the order of arrival. The FCFS scheduling approach is known by other names like first in-first out (FIFO), first come-first choice (FCFC), and others.

Regardless of the kind of jobs or requests it must execute, an FCFS mechanism is foreseeable because of its simplicity. Similar to a grocery checkout system, FCFS algorithms simulate actual customer service scenarios where customers who come first get treated immediately, regardless of the magnitude and intricacy of their encounter.

One of the most effective and independent scheduling algorithms is first come, first served because it only has to consider

Because it requires little to no human or natural intelligence (AI) intervention and doesn’t waste time ranking jobs and requests based on their urgency or degree of complexity, first come, first served is one of the most effective and autonomous scheduling algorithms. In addition, the CPU itself, rather than software or an alternative, more complicated work scheduling mechanism, is in charge of scheduling.

FCFS Meaning: What is it?

Here, we’ll concentrate on FCFS scheduling. FCFS Scheduling assists in streamlining the operations of the processor.

The scheduling algorithms are in charge of preventing processor monopolization by processes. An active program is called a process. There are three possible stages for this process: “Ready,” “Blocked,” and “Running.” The processes are kept in a list with details about their status, how much CPU time they have consumed, etc.

How does the FCFS algorithm implement?

First to arrive, First to serve, or [FCFS], is the most straightforward CPU scheduling strategy.

Workloads are handled in the order of arrival. Additionally, First Come, First Served management can result in subpar results since it ignores the system’s status or the resource requirements of the many operations.

Because it is an approach without eviction, this one has a high CPU reaction time because the process stays in the CPU until it is finished (Not Appropriate). Planning according to first to come, first served does away with the idea of process priorities.

The process that requires the greatest preparation time (and is first in the queue) will be chosen to receive the CPU.

Only two factors contribute to the CPU being used throughout the process execution:

  •  deliberately blocked while waiting for an occurrence (Printer, file, etc.).
  • When the process is finished.

FCFS and the Convoy Effect

The Convoy Effect in operating systems is demonstrated by the situation above. The term “convoy” refers to a circumstance in which several cars travel as a single unit in the current world. The convoy may slow down if one vehicle is forced to follow a considerably slower vehicle for an extended period. (Note: In sequential processing, this comparison only applies when there isn’t a secondary processing unit to share some of the load with the main processing unit.)

Despite the numerous disadvantages of utilizing an FCFS scheduler, there are many use situations where it is more efficient than intelligent scheduling techniques, which waste time re-evaluating each request’s priority after executing the previous one.

Advantages and disadvantages of FCFS


The use of FCFS, which is frequently regarded as the simplest CPU scheduling technique, is typical for many producers and supply chain companies. We will go over FCFS’ four main advantages—simplicity, user-friendliness, simplicity of implementation, and sequence integrity—to help you comprehend how it could improve order scheduling in your company.


FCFS has a few disadvantages that must be considered, even though it can benefit a company looking for simplicity in its demand scheduling operations. Because FCFS is relatively straightforward, it lacks some more intricate features in other order scheduling techniques. These negatives will be discussed, including a propensity for CPU processing over I/O, reduced device usage, and incompatibility with moment systems.

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