Question

Suppose a disk rotates at 5,400 revolutions per minute and has each surface divided intoo 16 sectors.

(a) What is the maximum posssible latency time? Under what circumstance will that occur?

(b) What is the minimum possible latency time? Under what circumstance will that occur?

(c) From (a) and (b), what will be the average latency time?

(d) What is the transmission time for one block?

Answer 1

Hard disk rpm speed is 5400 and hard disk is divided into 16 sectors.

Maximum possible rotates is calculated as follows:

Explanation:

$(60 \ seconds \ in \ minute \times 1000ms ) /rpm = 60000/5400=11.1111ms(milli \ seconds).$ To read and write the data on  hard disk taken rotation latency.

(a). Delay on ready and write depend on when the head is locate and data locating. Since it is 5400 is RPM and sectors are 16. It is approximated to 11.11 milli second by apply above formula.

(b). Data location is nearby head speed of RPM is increased.

(c). average latency time is 11.11 (milli seconds).

(d). approximated 11.11.