ext3, or third extended filesystem, is a journaled file system that is commonly used by the Linux kernel. It used to be the default file system for many popular Linux distributions. Stephen Tweedie first revealed that he was working on extending ext2 in Journaling the Linux ext2fs Filesystem in a 1998 paper, and later in a February 1999 kernel mailing list posting. The filesystem was merged with the mainline Linux kernel in November 2001 from 2.4.15 onward. Its main advantage over ext2 is journaling, which improves reliability and eliminates the need to check the file system after an unclean shutdown. Its successor is ext4.
RAR is a proprietary archive file format that supports data compression, error correction and file spanning. It was developed in 1993 by Russian software engineer Eugene Roshal and the software is licensed by win.rar GmbH. The name RAR stands for Roshal Archive.
In the maintenance of file systems, defragmentation is a process that reduces the degree of fragmentation. It does this by physically organizing the contents of the mass storage device used to store files into the smallest number of contiguous regions. It also attempts to create larger regions of free space using compaction to impede the return of fragmentation. Some defragmentation utilities try to keep smaller files within a single directory together, as they are often accessed in sequence.
Norton Utilities is a utility software suite designed to help analyze, configure, optimize and maintain a computer. The latest version of the original series of Norton Utilities is Norton Utilities 16 for Windows XP/Vista/7/8 was released 26 October 2012.
PageDefrag is a program, developed by Sysinternals, for Microsoft Windows that runs at start-up to defragment the virtual memory page file, the registry files and the Event Viewer's logs.
Dependency Walker or depends.exe is a free program for Microsoft Windows used to list the imported and exported functions of a portable executable file. It also displays a recursive tree of all the dependencies of the executable file. Dependency Walker was included in Microsoft Visual Studio until Visual Studio 2005 and Windows XP SP2 support tools. The latest version v2.2.10011 is not available on dependencywalker.com website but is included in the Windows Driver Kit v10.
Diskeeper is a discontinued defragmentation app, designed for Microsoft Windows. It was developed by Executive Software International, Inc., which later changed its name to Diskeeper Corporation, and is now called Condusiv Technologies. The final version of Diskeeper was released in March 2020. All of Diskeeper's features and functionality are now included in Condusiv's data performance software DymaxIO.
Microsoft Drive Optimizer is a utility in Microsoft Windows designed to increase data access speed by rearranging files stored on a disk to occupy contiguous storage locations, a technique called defragmentation. Defragmenting a disk minimizes head travel, which reduces the time it takes to read files from and write files to the disk. As a result of the decreased read and write times, Microsoft Drive Optimizer decreases system startup times for systems starting from magnetic storage devices such as a hard drive. However, defragmentation is not helpful on storage devices such as solid state drives, USB drives or SD cards that use flash memory to increase speeds, as these drives do not use a head. Defragmentation may decrease lifespan for certain technologies, e.g. solid state drives. Microsoft Drive Optimizer was first officially shipped with Windows XP.
Contig is a command line defragmentation utility for Windows developed by Microsoft as part of the Sysinternals Suite.
Windows Vista contains a range of new technologies and features that are intended to help network administrators and power users better manage their systems. Notable changes include a complete replacement of both the Windows Setup and the Windows startup processes, completely rewritten deployment mechanisms, new diagnostic and health monitoring tools such as random access memory diagnostic program, support for per-application Remote Desktop sessions, a completely new Task Scheduler, and a range of new Group Policy settings covering many of the features new to Windows Vista. Subsystem for UNIX Applications, which provides a POSIX-compatible environment is also introduced.
O&O Defrag is a Windows defragmentation utility sold by German software developer O&O Software. It has won several awards by PC journals and magazines, and is certified by Microsoft for all its current NTFS-based operating systems, including Windows 2000, Server 2003, Vista, 7, and 10.
Vopt is a Windows defragmentation utility sold by Golden Bow Systems. It is one of the oldest defragmentation products, and has supported MS-DOS and all versions of Microsoft Windows. The convenience of quick processing time is offset by less optimal performance, but when used in conjunction with the built-in optimization of the Windows prefetch folder, system performance is maintained without major reorganization of all the files on the drive.
Defraggler is a freemium defragmentation utility developed by Piriform Software, which can defragment individual files or groups of files on computer memory systems. Defraggler runs on Microsoft Windows; it has support for all versions since Windows XP. It includes support for both IA-32 and x64 versions of these operating systems.
UltraDefrag is a disk defragmentation utility for Microsoft Windows. Prior to version 8.0.0 it was released under the GNU General Public License. The only other Windows-based defragmentation utility licensed under the GNU GPL was JkDefrag, discontinued in 2008.
UltimateDefrag is a retail file-system defragmentation utility made by DiskTrix. An older version of the program is available as the UltimateDefrag Freeware Edition.
WinDirStat is a free and open-source graphical disk usage analyzer for Microsoft Windows. It presents a sub-tree view with disk-use percentage alongside a usage-sorted list of file extensions that is interactively integrated with a colorful graphical display. Created as an open-source project released under the GNU GPL, it was developed using Visual C++/MFC 7.0 and distributed using SourceForge. The project was inspired by SequoiaView, an application based on research done by the Visualization Section of the Faculty of Mathematics and Computer Science at the Technische Universiteit Eindhoven.
TeraCopy is a freemium file transfer utility designed as an alternative for the built-in Windows Explorer file transfer feature. Its focus is data integrity, file transfer reliability and the ability to pause or resume file transfers.
The following is a comparison of notable file system defragmentation software:
Auslogics Disk Defrag is a freemium software application for Microsoft Windows intended to defragment files and folders on a hard drive, consolidate free space, and optimize file placement using different criteria. It has an estimated 10 It is available in both free and "Pro" versions.
PerfectDisk is a defragmentation software product for Windows developed by Raxco.
