Computer people, disk driver cylinder question!?

Question

Requests come in to a disk driver for cylinders 12, 37, 15, 30, 6 and 11, in that order. The disk arm is currently at cylinder 13.

Closest Cylinder Next disk arm scheduling policy schedules the requests as:

A. 12, 11, 15, 6, 30 and 37
B. 12, 15, 11, 6, 37 and 30
C. 37, 30, 6, 15, 12 and 11
D. 6, 37, 15, 30, 11 and 12


I REALLY DONT UNDERSTAND THIS. IF ANYONE COULD HELP ME UNDERSTAND HOW YOU WORK IT OUT IT'D BE MUCH APPRECIATED!

Thanks

Answer 1

Hi,



OK, here is a definitive page on disk scheduling :-



http://www.comsci.us/os/notes/ch12.html



There are many way to set up disk scheduling but basically it is how the disk is set up to read the cylinders on the disk, that is where the data is stored.



So using your question above dependant on where the data is stored the arm needs to read the cylinders to get the data in the most efficient order, so you have to decide which answer is closest and perform the data request in the fastest way.



Have a look at the page in the link so you understand how it all works then you can decide which is the correct answer.



Arnak

Answer 2

just a guess. It will go the the closest cylinder each time (Closest Cylinder Next disk arm scheduling policy)... A. 12, 11, 15, 6, 30, 37

Answer 3

choose greater archives. Did you place in this no longer elementary disk as a alternative? what proportion beeps (what's the sequence)? jointly with 2 long beeps, 3 short (or in spite of). What laptop do you have, what no longer elementary force did you install? provide as many data as you are able to.