Doubt in Circular-Look and Circular-Scan

Question

In C-Look or in C-Scan when we take the circular move (from last to first), is this movement counted or not?

After searching I found that:

It should included: http://www2.cs.uregina.ca/~hamilton/courses/330/notes/io/node8.html

It should not included: http://www.cs.iit.edu/~cs561/cs450/disksched/disksched.html

I'm really confused. Please provide the reference of your solution.

Comments

This year one question came from C Look which included the transition from one extreme to another extreme..

Answer 1

See this  https://gateoverflow.in/39716/gate-2016-1-48

Tracks Numbered :  1-200
Track Requests : 98,183,87,12,14,124,65,67
Current Track : 53  (going towards end)

C-SCAN
53-65-67-98-122-124-183-200-0-14-37 ( ie Circular Elevator Algorithm Goes towards one end and it again Restart from Lower End in a circular fashion)

C-LOOK

53-65-67-98-122-124-183-14-37
Here also it goes in a circular fashion but unnecessary seek for 200 will not be present . Unlike Elevator algorithm Look algorithm need not go towards end .

Problem Source : Galvin

Comments

C-SCAN 
53-65-67-98-122-124-183-200-0-14-37 ( ie Circular Elevator Algorithm Goes towards one end and it again Restart from Lower End in a circular fashion)

While moving from 200 to 0 - should we add the head movement (200) or not?

C-LOOK

53-65-67-98-122-124-183-14-37 
Here also it goes in a circular fashion but unnecessary seek for 200 will not be present . Unlike Elevator algorithm Look algorithm need not go towards end . 

while moving rom 183 to 14 - should we add head movement(183-14=169) or not?

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Yes. we should add in both cases. see the GATE Question in the link

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@pC

Can you please help me understand how to decide to go on which side like in your example above you went right 53-65-67-98-122-124-183-14-37. Can't we go left like this 53-37-14-183-124-122-98-67-65.

Thanks in advance.