JKDefrag – An Intelligent Defragmenter for Windows

Whenever we talk about slow system performance, its almost certain that the first advice we will get is to defragment the hard disk drive. Lets understand what does it mean before we actually move on to JKDefrag.


During the daily usage we create and delete lot of files, When you create a new file OS tries to find the free space from the beginning of the disk and allocate the free space to files. This might lead to file being divided into multiple parts and these parts will be places in different areas.

Say you have a blank hard disk and you create 3 files i.e. file1 (10MB), file2 (5MB) and file3(20MB), lets assume they are organized serially on hard disk one after another.

| file1       | file2   |       file3        |
| (10MB)      | (5MB)   |       (20MB)       |

Now you delete file2 and create file4 which is of size 25MB. When you create file4 OS will try to find the free space from the beginning of the hard disk, in our case it will find that 5MB space is free  after file1 (released by deletion of file2 ) so it will divide file4 into two parts, first part of 5 MB will go between file1 and file2 and second part of 20MB will go after file3.

| file1       | file4A  |       file3        |       file4B       |
| (10MB)      | (5MB)   |       (20MB)       |       (20MB)       |

As shown in above table file 4 is divided into two parts and they are not continues this is what is called as fragmentation, this is just an example but in real life files can be divided into thousands of parts distributed all over the hard disk. When user wants to access this file OS need to find all the parts, Hard disk head needs to move to all over the hard disk and that’s what slows down the file access significantly.

Defragmenter tools will help you rearrange the files so that they are all continues. In our example a defragmenter may push file 3 further and allocate continues 25MB space for file4 between file1 and file2. Or it can move file1 and file2 one after another and allocate continues 25MB space for file4 after file3.


Even though all Windows versions have in-build defragmenter and it works quite well, it is not flexible. It has a fixed algorithm and it works on the whole hard disk. I wanted a defragmenter which is little more flexible and preferable GPL. JKDefrag meets all my requirements.

However, defragmenter is a tool that can change the whole data on your hard disk so you need to be very sure about what you are doing and tools you are using are reliable otherwise you might loose all your data. So before using it, I tried to understand whether they know what they are doing and I was highly satisfied with the information on there web page.

I like this tools for following main reasons:

  1. JKDefrag uses standard defragmentation APIs provided by Microsoft so JKDefrag does not access the hard disk directly but through a well defined interface provided by the Microsoft itself.
  2. JKDefrag is not only defragmenter but its also an optimizer. JKDefrag divides hard disk in three different areas i.e. Directories, Files and Space Hogs. Directories are placed in the beginning of the hard disk followed by regular files and finally Huge files (Space Hogs) which are not used frequently are placed towards end of the disk. This will ensure that frequently used files are towards the beginning of the disk . This arrangement makes file access much faster. It also keeps some free space in each area so that when new file is added it has the space in proper zone.
  3. JKDefrag provides different modes, Generally you will use the full time consuming mode first time and then use the fast mode everyday to defragment new data
  4. JKDefrag allows to sort the files based on name, size, access time etc
  5. JKDefrag allows to defragment a single file or directory or allows you to exclude set of files and directories as well
  6. JKDefrag comes with command line, GUI And Screen Saver version
  7. JKDefrag does not need any installation or setup, just download the binaries and use it
  8. JKDefrag can defragment Floppy disk, USB Drives
  9. JKDefrag works for Windows 2000/2003/XP/Vista/2008/X64
  10. It’s free software released under GPL.
  11. Support is available through forum

Overall its a very capable tool. Please visit the website and read all the information before using the tool.

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1 Response to JKDefrag – An Intelligent Defragmenter for Windows


    I totally agree that the default Windows defragmentation utility that comes with your Windows Operating System has reduced functionality!

    I have been using a FREE utility for over 2 years with fantastic results. It defrags all my drives (including partitions and portable hard drives that are connected to the computer) all in one run! It is called JKDefrag and can be found at http://www.jkdefrag.com.

    Highly recommended and did I mention it is FREE??? lol

    Kelvin has over 20 years of experience working with computers. From data entry to programming and computer optimization techniques. Kelvin runs a blog on how YOU can optimize your computer for speed and security at http://optmypc.com with information that you can use today.

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