|Free GNU software|
JkDefrag is a disk defragmenter and optimizer for Windows 2000/2003/XP/Vista/2008/X64.
Completely automatic and very easy to use, fast, low overhead, with several optimization strategies, and can handle floppies, USB disks, memory sticks, and anything else that looks like a disk to Windows.
Included are a Windows version, a commandline version (for scheduling by the task scheduler or for use from administrator scripts), a screensaver version, a DLL library (for use from programming languages), versions for Windows X64, and the complete sources.
Defragmentation and optimizing will not only make a harddisk faster, but also lengthen it's life span. The disk will have less work to do and therefore have less wear and tear. Secondly, the sorting optimization strategies (see the "-a" option) will refresh all the magnetic data on your harddisk. However, defragmenting and optimizing is work, so excessive defragmenting and optimizing can actually cause more wear and tear than it prevents. JkDefrag is therefore set for "fast" optimization by default, intended to be used on a daily basis. The other optimizations should only be used occasionally.
- What is "disk fragmentation"?
Imagine a book split into several parts, some pages are over here, other pages in another room on another floor altogether. You will have to walk a lot when you need to read the book. It may sound silly, but this is exactly what happens to files on your harddisk. Defragmentation will put all the parts (fragments) back together, making your computer a lot faster.
What is "disk optimization"?
Imagine a big library with lot's of books, spread out all over the building and not sorted whatsoever. There is an index telling you exactly where every book is, but you will have to walk a lot when you need several books. This is exactly what happens on your harddisk, the files that belong to an application can be all over the place, anywhere on the harddisk. Optimization will bring all the files together in one place, leaving the rest of the harddisk empty, and will sort the files, for example alphabetically.
- How safe is it?
- JkDefrag is based on the standard defragmentation API by Microsoft, a system library that is included in Windows 2000, 2003, XP, Vista, and 2008.
- Most defragmenters are based on this API, including commercial defragmenters.
- Basically all JkDefrag does is send "move this file to that location" commands to the API. It does not touch the disk by itself, and is therefore extremely solid. If your disks use NTFS then you're even safe when the computer crashes in the middle of defragmenting.Nevertheless, it's still a good idea to backup before defragmenting, just like with other defragmenters, because the heavy use of the harddisk may trigger a hardware fault (disk crash), and/or overheating (disk, power supply, controller chipset, etc.).
- Do I have to "checkdisk" before running JkDefrag?
- Feel free to do so, but it's not necessary. JkDefrag is totally solid and cannot get confused by a corrupted disk. And even if it could then nothing bad can happen, because JkDefrag does not write to disk itself. Everything is done through the Windows defragmentation API, and Windows is quite smart about handling corrupted disks.
- How do I specify an option, or select a single disk (or folder or file)?
- If you don't know how to use the Windows commandline, then take a look at the GUI wrappers, see the "Contributed by other people" chapter.
Another way is to create a shortcut to "JkDefrag.exe", open the properties of the shortcut, and add the desired commandline options (for example "-a 7") or the name(s) of the disk/folder/file (for example "C:") to the end of the "target" line. For example:
- "C:\JkDefrag\JkDefrag.exe" -a 7
- "C:\JkDefrag\JkDefrag.exe" D:
Tip: In the same properties window you can select "minimized".
Tip: See the JkDefrag "-q" option to exit automatically when finished.
- Where is the Stop button?
- All versions of JkDefrag can be stopped safely at any time, there is no risk of losing data or corrupting your disk.
You can use all the usual ways to stop a Windows program, such as pressing ALT-F4,
clicking the 'x' in the top-right corner, via the pull-down menu in the taskbar, or by killing the program via the task manager or another utility.
The commandline program can be stopped the same way, plus by pressing CTRL-C, or BREAK. It may take a bit of time for the program to actually stop, JkDefrag will finish the current file in the background.
Release date: August 31, 2008
|JkDefrag-3.36.zip||Download for Windows 2000/2003/XP/Vista/2008||479kb|
|JkDefrag64-3.36.zip||Download for X64 versions of Windows 2003/XP/Vista/2008||488kb|
|• Grey:||in use by unknown data|
|• Pink:||system files|
|beginning of the disk|
JkDefrag option Gui
A. Main Strategy:
- - analysing only (action 1)
- - analysing and defragmenting (action 2)
- - defragmenting and optimising (action 3)
optimisation strategy is very suitable for day-to-day use. It moves a
minimum of data on the hard disk and finishes very quickly, but will
not fill all the gaps on the disk. The strategy scans for gaps on the
disk and fills them with files from above.
- - full optimisation (action 4) [since v3.14 removed]
optimisation strategy is for incidental use once in a while. It takes a
lot of running time and data movement because it tries to fill all the
gaps on the disk. The strategy is the same as for fast optimisation,
plus the files just above a gap are moved away until the gap can be
completely filled with files from above.
- - sorted optimisation (actions 7 - 11)
the sorting optimizations will create fragments. This is by design, it
is not a bug. These sorting optimizations are for incidental use once
in a while. They take a lot of running time and data movement because
they rewrite all the data on the disk. The strategies vacate a small
area on disk and then fill it up again with the files in the selected
- sort by name (action 7): very good for fast program starting. The files used by a particular program will be very close together on disk.
- sort by size (action 8): placing all the small files together at the begin of the disk will dramatically reduce the average file seek time.
- sort by last access (action 9): files that have not been accessed in a while are probably unimportant and are best sorted to the back.
- sort by last change
(action 10): placing files together that change a lot (for example
databases and log files) will speed up regular operation of the system.
- sort by creation time (action 11): the oldest files on the disk are likely to be important system files, for example used when Windows is booting.
- - force together (action 5):
for partition resizing. All movable files are moved to the beginning of
the disk, even if it means fragmenting them to fill gaps that cannot be
- - move to end of disc (action 6):
all the files to the end of the disk, making more room at the beginning
of the disk. Intended for big and rarely used files such as log files,
backup archives, installation files, and such.