FCFS Full Form

What is the full form of FCFS?

The full form of FCFS is First Come First Serve. FCFS is a scheduling algorithm that schedules processes in the order they arrive in the queue. It is also known as a non-preemptive scheduling algorithm, meaning that once a process has started execution, it cannot be interrupted by another process until it completes its execution. In FCFS, the process that arrives first is executed first, and so on. It is the simplest and most intuitive scheduling algorithm, and is used in various systems such as operating systems, databases, and real-time systems.

An example of FCFS in action would be a queue at a ticket counter or a customer service desk. The first person in line will be helped first, and then the next person in line, and so on. It's worth noting that FCFS can lead to longer waiting times for the processes that arrive later in the queue, as they have to wait for the processes that arrived before them to complete their execution. This can lead to a situation known as "starvation" where some processes may never get a chance to execute if new processes keep arriving..

Characteristics

First Come First Serve Scheduling is the full form of FCFS scheduling.The queued processes and requests are automatically carried out in the order they were received by the FCFS Scheduling algorithm. The first job that enters the queue is given to the CPU, followed by the second and so on. The most straightforward CPU scheduling algorithm is FCFS, which utilises a FIFO queue. First In First Out is referred to as FIFO.

The FCFS scheduling algorithm puts the newly arrived processes/jobs at the end of the line. As a result, the CPU gives its allocation to the processes that request it first. Any process that joins the FIFO queue has its Process Control Block (PCB) linked to the tail of the queue.The initial process is assigned to the CPU as it becomes available. Even if the CPU begins a longer job, many shorter ones must wait while it is processing. The majority of operating system batches support the FCFS scheduling algorithm.

Why Use FCFS Scheduling?

• FCFS scheduling employs a non-preemptive strategy, which means that once the CPU grants control to a process, it won't preempt until the job has finished.

• It adheres to the selection criteria for arrival time.

• The processor chooses the first task in the ready queue, and it executes it until it is finished.

• Both preemptive and non-preemptive scheduling algorithms are supported.

• Every job runs according to the principle of first come, first serve.

• In the event of a tie, smaller processes take the lead.

• Because of the way FCFS operates, the average wait time is quite long.

• In the long run, it is practical to use and implement the algorithm.

• The procedure is simple to understand.

• Every execution adheres to the First In First Out principle (FIFO) ready queue.

Pros of Using FCFS Scheduling

• The algorithm is simple to comprehend and use.

• Simple procedures are simple to handle and understand.

• Since there is no consideration of priority, FCFS is a very fair algorithm that prioritises the order in which processes are executed.

• The implementation organises the data structure using a FIFO queue, simplifying each step along the way.

• FCFS doesn’t lead to starvation.

• Non-preemptive scheduling is used. No project is paused as a result.

• It is the easiest to operate and programme form of the CPU scheduling algorithm.

• Since there is no context switching between processes, the FCFS algorithm is better for processes with relatively long burst times.

Cons of Using FCFS Scheduling

• The FCFS method performs poorly.

• Because of the non-preemptive scheduling, the average wait time is too long.

• Once a process has been given access to the CPU, it does not release it until execution is complete.

• Due to the need to wait for one large project at the front to finish before moving on, the convoy effect occurs.

• It might not be suitable for interactive systems since it does not guarantee a quick response time.

• FCFS does not give any process or burst time any priority.

• FCFS is incredibly ineffective due to its simplicity.

• The time-sharing systems are not compatible with this algorithm.