The blog provides study material for Computer Science(CS) aspirants. Mostly says "material nahi milta, padhun kahan se.", I think If you can not find content on the Internet, then you are not a CS student. Dedicated to (Prof. Rakesh Kumar, DCSA, K.U.Kurukshetra, HARYANA, INDIA)- "Ek teacher ka bahut jyada padhna, bahut jyada jaroori hota hai."
Saturday, 28 December 2013
Disk Scheduling Algorithms
Relatively speaking, retrieving data from hard disk drivers is always slow compared to CPU and memory access due to the mechanical nature of the magnetic disk. Disk arm movement is very expensive operation therefore operating systems use disk scheduling algorithms to reduce seek time. Below you can find a summary of some of the well known disk scheduling algorithms. The algorithm receives a queue of request positions (track numbers) and the current head position. The output of the algorithm is the order in which the requests are serviced.
First Come First Serve (FCFS)
Requests are serviced in the order in which they arrive
The algorithm is easy to implement
Bad algorithm as it may involve lots of unnecessary seek distance
Here is an example assuming we have 200 cylinders: