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Disk Defragmentation in Operating System

  • Last Updated : 12 Nov, 2020

Fragment a small piece that comes from something large.

Disk Fragmentation : Fragmentation of disk means allocating data in non-sequence form. Usually, data is stored in hard drive in sequence form and data header is keep following incoming data so that it is easy to read data efficiently but when we delete some older data from this sequence. Sequence of data management is disturbed and data is looking like scatter form and also when we update older data with a bigger size of data Operating System split entire data into small packets and store data in different locations of storage area.

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Disadvantages of the Fragmentation :



  1. Read and Write time of data in disk increase because the data header has sections to move in difference storage section of disk.
  2. Efficiency and performance of disk decreases.
  3. Usage of disk can be reached to 100 percent.
  4. Acquire more storage section results decrease volume of disk.
  5. Health of hard disk may be affected due to Fragmentation.
  6. Slow boot-up time of Machine.
  7. Errors in and conflict between applications.

Types Of Fragmentation :

  • Internal Fragmentation –
    Internal fragmentation happens when memory is split into mounted sized blocks. Whenever a method request for memory, mounted sized block is allotted to method. just in case memory allotted to method is somewhat larger than memory requested, then distinction between allotted and requested memory is that internal fragmentation.
  • External Fragmentation
    External fragmentation happens when there’s a sufficient quantity of area within memory to satisfy the memory request of a method. however, the process’s memory request cannot be fulfilled because the memory offered is during a non-contiguous manner. Either you apply a first-fit or best-fit memory allocation strategy it’ll cause external fragmentation.
  • Data Fragmentation –
    In data fragmentation, data is stored in non-sequential form.

Fragmented Disk

Defragmented Disk

Disk Defragmentation : In this process, all scattered fragments (data) rearrange in such that they come in sequence form with further utility program available in Windows. In this process program first, check percentage of the fragment available in disk then Defragment all disk as can as possible.

Defragmentation of Disk :

  1. Right-click on any drive available on your computer which we want to Defragment then click on the tools section and after optimize.

    2. After Optimize it will check the total fragmented available in the selected disk and click on Optimize.

3. It will take some time and after this process 0% Fragment will be present in the disc.

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