Disk Scheduling

Description

When disk requests arrive at the disk device, they are queued for service and a disk scheduling algorithm is used to decide which of a waiting queue of disk requests to serve next.

Parameters

n: number of requests

Table of Algorithms

Name	Year	Time	Space	Approximation Factor	Model	Reference
FCFS	1979	$O(n)$	$O({1})$ auxiliary	Exact	Deterministic
SSTF	1979	$O(n*log n)$ with binary tree	$O(n)$ auxiliary	Exact	Deterministic	Space
SCAN	1979	$O(n*log n)$	$O(n)$ auxiliary	Exact	Deterministic	Space
LOOK	1979	$O(n*log n)$	$O(n)$ auxiliary	Exact	Deterministic
C-SCAN	1979	$O(n*log n)$	$O(n)$ auxiliary	Exact	Deterministic
C-LOOK	1979	$O(n*log n)$	$O(n)$ auxiliary	Exact	Deterministic

Time Complexity Graph

Space Complexity Graph

Time-Space Tradeoff