Magnetic discs store data on parallel tracks (tracks) on eachdisc. Head-reader moves
between the tracks to read the data. Serial receives a request forreading, there
as a request i is in on track ti. Initially, the head-reader is ontrack c.
these n requests can be done in any order, so we want to executethem in the order that
minimizes the total travel time of the headlamp. If the head-readeris on track c and needs to
go to track ti, then its moving time | c – ti | time units. Forexample, if a head-reader is on
track 140 and the requests are {100, 50, 190}, then
OR
OR