# If a disk drive’s rotational speed is 10000 revolutions per minute, what is its average rotational laten

If a disk drive’s rotational speed is 10000 revolutions per minute, what is its average rotational latency?

A.
0.003 milliseconds

B.
0.05 milliseconds

C.
3 milliseconds

D.
5 milliseconds

## 6 Comments on “If a disk drive’s rotational speed is 10000 revolutions per minute, what is its average rotational laten”

1. SP says:

(1 / (RPM / 60)) * 0.5 * 1000

Or, in other words:

30000 / RPM

Result in ms.

So 30000 / 10000 = 3 miliseconds

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2. SP says:

Forgot to explain:
The average rotational latency for a disk is half the amount of time it takes for the disk to make one revolution

so (1 / (RPM / 60)) * 0.5 * 1000

0.5 is for the half
RPM/60 to get it in seconds and * 1000 to covert to miliseconds

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3. Must says:

rpm = rotational per minute

(½)/ (X/60)= “60/2X”

X is 10000 > 10k = 60/(2×10) = 3 ms

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4. L. Freitas says:

RPM = 10000

Average Seek Time is equal a half of a turn,

Rotacional per second (rps) = Rotational per minute/60.

A half a turn is (1/2 or 0,5)/(rps).

R = (0,5)/(RPM/60)
R = (0,5)/(10000/60)
R = 0,5 / 166.6 <- rps
R = 0,003 seconds or 3 milliseconds. :)

\O/ \O/ \O/

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