Overview of CPU Scheduling Algorithms

CPU scheduling algorithms are used by the operating system to determine which process should be executed next. The goal of these algorithms is to improve system performance, minimize response time, and ensure fairness.

There are several factors that need to be taken into account when scheduling CPU time for processes. These include the priority of the process, the time required for the process to complete its task, the amount of CPU time already used by the process, and the amount of time the process has spent waiting for input or output operations.

Different CPU scheduling algorithms use different techniques to determine which process should be executed next. Some algorithms prioritize processes based on their importance, while others prioritize processes based on their execution time. Some algorithms use a fixed time slice for each process, while others dynamically allocate time slices based on the requirements of the processes in the system.

In general, the goal of all CPU scheduling algorithms is to maximize system efficiency and provide the best possible user experience by ensuring that processes are executed in a timely and efficient manner.

Types of CPU Scheduling Algorithms

• First-Come, First-Served (FCFS): This algorithm schedules processes in the order they arrive in the ready queue. The first process in the queue gets to use the CPU until it completes or gets blocked.
• Shortest Job First (SJF): This algorithm schedules the process with the shortest burst time next, ensuring that the shortest job is completed first. This algorithm is known to be optimal, but it requires knowledge of the burst time of each process in advance.
• Priority Scheduling: This algorithm assigns priorities to each process based on its importance or resource requirements. The higher priority process gets to use the CPU first, and lower priority processes have to wait.
• Round Robin (RR): This algorithm allocates a fixed time slice to each process in the ready queue, and processes are scheduled in a circular manner. If a process has not completed its work during its time slice, it is preempted, and the next process gets a chance to execute

Overview of Disk Scheduling Algorithms

Disk scheduling algorithms are used by the operating system to manage the access of the disk by multiple processes. The goal of these algorithms is to minimize disk access time, increase system throughput, and ensure fairness.

Disk scheduling algorithms take into account the physical characteristics of the disk, including its rotational speed, seek time, and transfer rate, as well as the location of data on the disk. Different disk scheduling algorithms use different techniques to determine which process should be given access to the disk next.

Types of Disk Scheduling Algorithms

• First-Come, First-Served (FCFS): This algorithm serves requests in the order they arrive in the queue. The first request in the queue is served first, regardless of its location on the disk.
• Shortest Seek Time First (SSTF): This algorithm serves the request that is closest to the current position of the disk head, minimizing the seek time required to access the data.
• SCAN: This algorithm moves the disk head in one direction, serving all requests in that direction until there are no more requests in that direction, then reverses direction and serves all requests in the other direction.
• C-SCAN: This algorithm is similar to SCAN but always moves the disk head in one direction, serving requests in that direction and wrapping around to the beginning of the disk when the end is reached.
• LOOK: This algorithm is similar to SCAN but only serves requests that are in the same direction as the disk head, reducing the average seek time.