The LOOK algorithm (wiki) is the same as the SCAN algorithm in that it also honors requests on both sweep direction of the disk head, however, this algorithm "Looks" ahead to see if there are any requests pending in the direction of head movement. If no requests are pending in the direction of head movement, then the disk head traversal will be reversed to the opposite direction and requests on the other direction can be served.

In wiki there is a line which says

LOOK behaves almost identically to Shortest seek time first (SSTF), but avoids the starvation problem of SSTF.

Is it(LOOK) always successful in avoiding starvation or there might be some order of disk request where it may lead to starvation.


The wiki article also says that

This is because LOOK is biased against the area recently traversed, and heavily favors tracks clustered at the outermost and innermost edges of the platter.

However, I found it confusing.

The reason why LOOK avoids starvation is quite easy: For any request, it will be served within a finite time interval $t$ (since it is submitted): Suppose the number of cylinders in a disk is $N$, then we can set $t = 2N$.


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