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How does an elevator algorithm work?
The elevator algorithm is a simple algorithm by which a single elevator can decide where to stop, is summarized as follows: Continue traveling in the same direction while there are remaining requests in that same direction.
Why scan algorithm is also called elevator algorithm?
SCAN: In SCAN algorithm the disk arm moves into a particular direction and services the requests coming in its path and after reaching the end of disk, it reverses its direction and again services the request arriving in its path. So, this algorithm works as an elevator and hence also known as elevator algorithm.
What is Cscan algorithm?
Circular SCAN (C-SCAN) scheduling algorithm is a modified version of SCAN disk scheduling algorithm that deals with the inefficiency of SCAN algorithm by servicing the requests more uniformly. Like SCAN (Elevator Algorithm) C-SCAN moves the head from one end servicing all the requests to the other end.
What is round robin algorithm explain with example?
Round robin is a pre-emptive algorithm. The CPU is shifted to the next process after fixed interval time, which is called time quantum/time slice. The process that is preempted is added to the end of the queue. Round robin is a hybrid model which is clock-driven.
What is the elevator algorithm in Windows 10?
The elevator algorithm (also SCAN) is a disk – scheduling algorithm to determine the motion of the disk’s arm and head in servicing read and write requests. This algorithm is named after the behavior of a building elevator, where the elevator continues to travel in its current direction (up or down) until empty,…
How are requests serviced in the elevator algorithm?
As additional requests arrive, requests are serviced only in the current direction of arm movement until the arm reaches the edge of the disk. When this happens, the direction of the arm reverses, and the requests that were remaining in the opposite direction are serviced, and so on.
Which is a variation of the circular elevator algorithm?
One variation of this method ensures all requests are serviced in only one direction, that is, once the head has arrived at the outer edge of the disk, it returns to the beginning and services the new requests in this one direction only (or vice versa). This is known as the “Circular Elevator Algorithm” or C-SCAN.
How does the elevator algorithm work when the drive is idle?
When a new request arrives while the drive is idle, the initial arm/head movement will be in the direction of the cylinder where the data is stored, either in or out. As additional requests arrive, requests are serviced only in the current direction of arm movement until the arm reaches the edge of the disk.