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Q96552: What Defragmenter Does & How It Works with 3rd-Party Utilities

Article: Q96552
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:6.0
Operating System(s): 
Keyword(s): 
Last Modified: 21-NOV-1999

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The information in this article applies to:

- Microsoft MS-DOS operating system version 6.0 
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SUMMARY
=======

Microsoft Defragmenter reorganizes data on MS-DOS drives so that it can be
retrieved faster.

MORE INFORMATION
================

MS-DOS organizes data on the hard disk into a series of clusters (allocation
units) and then tracks which files are using which clusters through directory
structures and the file allocation tables (FATs). Neither users nor applications
need to know exactly where specific data is located on the hard disk. When an
application needs a file, it simply asks MS-DOS to get it.

Over time, pieces of files may be spread all over the hard disk. When this
occurs, retrieving files requires more time. Defragmenter reorganizes the
clusters for faster access. (For example, information is stored at the front of
the disk, and parts of files are regrouped together). Defragmenter uses
interrupt calls 25H and 26H to move the information stored in one cluster to
another, directly updating the FATs and directory structures.

Defragmenter operates at nearly the same level as MS-DOS. However, it still uses
MS-DOS and is protected from direct interactions with the following:

- Third-party partitioning utilities that modify or translate disk geometry
  (such as Disk Manager and SpeedStor)

- DoubleSpace and third-party drive compression utilities

Additional query words: 6.00 3rd-party defrag

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Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS600
Version           : MS-DOS:6.0

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