$8.(12\%)$ Suppose that a disk drive has $2,000$ cylinders, numbered $0$ to $1999.$

The drive is currently serving a request at cylinder $150,$ and the

previous request was at cylinder $130.$ The queue of pending requests,

in FIFO order is: $100,$

$100,1500,900,1750,950,1600,1000,1800,540$

Starting from the current head position, what is the total distance $($in

cylinders$)$ that the disk arm moves to satisfy all the pending requests

for each of the following disk$-$scheduling algorithms $?$

$($a$)$ FCFS

$($b$)$ SSTF

$($c$)$ SCAN

$($d$)$ LOOK

$($e$)$ C$-$SCAN

$($f$)$ C$-$LOOK