Computer Science - Computer Fundamentals - Discussion

Please tell me what is down time, seek time and access time?

The read write head have to rotate to find correct sector, so time taken to rotate is called rotational delay.

Access time is the time between when one access request has begun and when the next one can begin.

Seek time is the time it takes for the head to move to the data area sought.

Seek time is a component of access time, and will therefore always be smaller. Note, however, that these times as given in specifications will always be averages, since the seek time can vary wildly, depending on how far the head is from the data area it needs to read or write.

Seek Time: It is the time taken by the disk head to position itself over the desired track.

Rotational Latency: Once the desired track has been found, the disk needs to rotate until the required sector aligns itself according to the rotation head. This time taken is referred to as Rotational Delay or Rotational Latency.

Access Time = Seek Time+Rotational Latency.

Seek Time ; is the time to find & get the desired track.

Rotational Delay / Rotational Latency : is the time to find & get the desired sector out of the already Known track. (this time is after the Seek Time).

Access Time = (Seek Time + Rotational Latency).

Seek time is the time taken by the disk head to position itself over desired track.

What is Down time? Explain, please.