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Difference Between Seek Time and Transfer Time in Disk Scheduling

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The head’s seek time is the time it takes to move from the current track to the one containing the data. The amount of time needed to move data from the disc to the host system is called the transfer time. In hard drives, a head is present which is supposed to write or read from the magnetic disk. In this article we are going to discuss what are seek and transfer times and check the differences between them, Below is a detailed discussion of seek and transfer times:

What is Seek Time?

The amount of time it takes a hard disc controller to find a particular piece of stored data is known as the seek time. Depending on where the head is when the read/write request is received, the seek time may change.

The read/write head of a disc shifts into the proper position whenever anything is read from or written to it. Seeking refers to the actual physical location of the disc’s read/write head. The seek time is the amount of time the disc’s read/write head needs to go from one disc to another. It is the time that the head of a disc takes to move from one track to another track on a disk. Seek Time can vary a lot upon where the head is present right now when the read/write request is sent, hence Average Seek Time is used more widely. 

For a clearer picture, consider a hard disk of concentric circles called tracks, Suppose you want to fetch some data. Seek Time is the time needed for the head to move from its current track to the one where the data is present, Even after this it might have to wait for some more time because the data is present on the opposite side of the track and this delay is called Rotational Latency but this isn’t counted in Seek Time. 

Depends on: 

  • Speed of read/write head
  • Distance between current and final position
Seek Time
Seek Time

What is Transfer Time?

Transfer time is the time taken to transfer the data from the disk. It varies on the rotational speed of the disk, the faster a disk rotates the faster we can read data, to and on the number of bytes on one track which can also be called the density of the disk, the faster we can transfer data hence the lower transfer time. The amount of time needed to move data from the disc is called the transfer time. It fluctuates according to the disk’s spinning speed. Data may be read more quickly from a disc the quicker it rotates. The density of the disc is also known as the amount of bytes on a single track.

Depends on: 

  • Rotational Speed of a disk, faster is better
  • Track and Sector Density, more is better
  • Amount to data to be Transferred

Difference Between Seek Time and Transfer Time

Seek Time Transfer Time
Time taken by the head to move from current track to the one where data is present. Time taken to transfer data from the disk to the host system.
Can vary a lot depending upon the distance between current and final position and how it has been instructed to go. T = b/rN 
T is Transfer time, b is number of bytes to be transferred, N is number of bytes on a track and r is rotational speed in Rps
Measure in Average Seek Time Measure in Data Transferred in a unit time i.e. Second
Usually in between 10-20 ms, depending upon the RPS and grade of Drive It takes about 1 sec to transfer 30-60MB of data

Eliminating unnecessary head development and making effective planning estimates.

Maximising the components of information exchange while making use of high-speed interfaces.

Navigational distance, machine capabilities, and scheduling algorithm.

Components of information transfer, rotational speed, and information thickness.

Frequently Asked Questions on Seek Time and Transfer Time – FAQs

How does seek time impact disk performance?

The operating system or the hard drive’s controller hardware can have extra overhead.

What is the relationship between seek time and transfer time?

Seek time and Transfer time are not related to each other.

What are some common techniques used to reduce seek time?

Some common techniques include SCAN , C-SCAN and LOOK. 

What is the relationship between seek time and search time?

The read/write head’s whole movement across the platter is known as the “search time,” while the magnetic disk’s rotation until it is in the ideal position beneath the read/write head is also known as the “search time.” Some individuals mix up the two because they are unaware of the components of the magnetic disc.


Last Updated : 22 Feb, 2024
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