Microsoft Drive Optimizer (formerly Disk Defragmenter) is a
utility
In economics, utility is a measure of a certain person's satisfaction from a certain state of the world. Over time, the term has been used with at least two meanings.
* In a normative context, utility refers to a goal or objective that we wish ...
in
Microsoft Windows
Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...
designed to increase data access speed by rearranging
files stored on a
disk to occupy
contiguous
Contiguity or contiguous may refer to:
*Contiguous data storage, in computer science
*Contiguity (probability theory)
*Contiguity (psychology)
*Contiguous distribution of species, in biogeography
*Geographic contiguity
Geographic contiguity is t ...
storage locations, a technique called
defragmentation
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 ...
. Microsoft Drive Optimizer was first officially shipped with
Windows 95
Windows 95 is a consumer-oriented operating system developed by Microsoft and the first of its Windows 9x family of operating systems, released to manufacturing on July 14, 1995, and generally to retail on August 24, 1995. Windows 95 merged ...
.
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
A solid-state drive (SSD) is a type of solid-state storage device that uses integrated circuits to store data persistently. It is sometimes called semiconductor storage device, solid-state device, or solid-state disk.
SSDs rely on non-v ...
,
USB drives or
SD cards that use
flash memory
Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for t ...
to increase speeds, as these drives do not use a head. Doing so may decrease lifespan for these types of devices.
From Windows 8 onwards, the program was renamed to Microsoft Drive Optimizer, with some references changed to say ''Defragment and Optimize Drives'' or simply ''Optimize Drives''.
Early history
As early as the end of 1982, the
IBM PC DOS
IBM PC DOS (an acronym for IBM Personal Computer Disk Operating System),Formally known as "The IBM Personal Computer DOS" from versions 1.0 through 3.30, as reported in those versions' respective COMMAND.COM outputs also known as PC DOS or IBM ...
operating system that shipped with early
IBM Personal Computer
The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible ''de facto'' standard. Released on August 12, 1981, it was created by a ...
s included a Disk Volume Organization Optimizer to defragment the 5ΒΌ-inch
floppy disk
A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...
s that those machines used. At this time,
Microsoft
Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...
's
MS-DOS
MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...
did not defragment hard disks. Several third party software developers marketed defragmenters to fill this gap. MS-DOS 6.0 introduced Microsoft Defrag.
Windows NT
Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...
, however, did not offer a Defrag utility, and
Symantec was suggested by others as a possible alternative for the utility.
Initial releases of Windows NT lacked a defragmentation tool. Versions through
Windows NT 3.51 did not have an
application programming interface
An application programming interface (API) is a connection between computers or between computer programs. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standard that des ...
for moving
data cluster
In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. For most disks, each sector stores a fixed amount of user-accessible data, traditionally 512 bytes for hard disk drives (HDDs), and 2048 byte ...
s on hard disks.
Executive Software, later renamed
Diskeeper Corporation, released
Diskeeper defragmentation software for Windows NT 3.51,
[ which shipped with a customized version of the NT kernel and file system drivers that could move clusters.
Microsoft included file system control (FSCTL) commands to move clusters in the Windows NT 4.0 kernel,][ which worked for both ]NTFS
NT File System (NTFS) (commonly called ''New Technology File System'') is a proprietary journaling file system developed by Microsoft in the 1990s.
It was developed to overcome scalability, security and other limitations with File Allocation Tabl ...
and FAT
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers specif ...
partitions. However, Windows NT 4.0 did not provide a graphical or command-line user interface.[
]
Debut and early versions
Disk Defragmenter first shipped as part of Windows 95
Windows 95 is a consumer-oriented operating system developed by Microsoft and the first of its Windows 9x family of operating systems, released to manufacturing on July 14, 1995, and generally to retail on August 24, 1995. Windows 95 merged ...
and later shipped with Windows 98
Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the second operating system in the 9x line, as the successor to Windows 95. It was Software ...
and Windows Me
Windows Me (Millennium Edition) is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the successor to Windows 98, and was released to manufacturing on June 19, 2000, and t ...
, licensed from Symantec Corporation. It could be scheduled using a Maintenance Wizard and supported command line switches. In the version of Disk Defragmenter included with Windows 95 and 98, if the contents of the drive changed during defragmentation, the program paused, rescanned the entire drive, and then resumed the process from where it had left off. This quirk was removed in the Windows Me version of Disk Defragmenter.
Disk Defragmenter in Windows 2000
Windows 2000 is a major release of the Windows NT operating system developed by Microsoft, targeting the server and business markets. It is the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RT ...
was a stripped-down version of Diskeeper, licensed from Diskeeper Corporation. It uses the following techniques:
# Moving all the index or directory information to one spot. Moving this spot into the center of the data, i.e. one third of the way in, so that average head travel to data is halved compared to having directory information at the front.
# Moving infrequently used files further from the directory area.
# Obeying a user-provided table of file descriptions to emphasize or ignore.
# Making files contiguous so that they can be read without unnecessary seeking.
In Windows 2000 and later operating systems, Microsoft Drive Optimizer has the following limitations:
* It does not defragment files residing in the Recycle Bin or files that are in use. In particular, this includes the registry, page file and hibernation file.
* Prior to the Windows Vista release, only one volume could be analyzed or defragmented at a time and only one instance could run.[Disk Defragmenter Limitations in Windows 2000, Windows XP, and Windows Server 2003](_blank)
/ref>
* Only local volumes can be defragmented; network volumes are not supported.
* The GUI version prior to Windows Vista cannot be scheduled. However, the command line utility since Windows XP and later can be scheduled.
* Unlike previous versions, the GUI version in Windows Vista does not display a map of disk fragmentation, nor does it display progress during defragmentation.
In addition, the Windows 2000 version has the following limitations which were removed in Windows XP:
* Defragmenting NTFS
NT File System (NTFS) (commonly called ''New Technology File System'') is a proprietary journaling file system developed by Microsoft in the 1990s.
It was developed to overcome scalability, security and other limitations with File Allocation Tabl ...
volumes with cluster sizes larger than 4 kilobytes (KB) is not possible.
* It is not possible to perform fine-grained movement of uncompressed NTFS file data in Windows 2000. Moving a single file cluster also moves the 4 KB part of the file that contains the cluster.
* EFS encrypted files are not defragmented.
Windows XP and Server 2003
Windows Disk Defragmenter was updated to alleviate some restrictions. It no longer relies on the Windows NT Cache Manager, which prevented the defragmenter from moving pieces of a file that cross a 256KB boundary within the file. NTFS
NT File System (NTFS) (commonly called ''New Technology File System'') is a proprietary journaling file system developed by Microsoft in the 1990s.
It was developed to overcome scalability, security and other limitations with File Allocation Tabl ...
metadata files can also be defragmented. A command-line tool, ''defrag.exe'', has been included, providing access to the defragmenter from cmd.exe
cmd.exe, a.k.a. Command Prompt, is a shell program on later versions of Windows ( NT and CE families), OS/2,, eComStation, ArcaOS, and ReactOS. In some versions of Windows ( CE .NET 4.2, CE 5.0 and Embedded CE 6.0) it is referred to as ...
and Task Scheduler. In Windows XP, if the Master File Table (MFT) is spread into multiple fragments, defrag.exe and the GUI version can combine the MFT fragments during defragmentation. Windows XP and later has introduced ''Boot Files Defragment'' function, this function is enabled by default and can be disabled in Registry.
Windows Vista and Server 2008
In Windows Vista
Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...
, Disk Defragmenter includes an option to automatically run at scheduled times using Task Scheduler and uses low CPU priority and the newly introduced low priority I/O algorithm so that it can continue to defrag using reduced resources (less CPU and disk read/write activity) when the computer is in use. The user interface has been simplified, with the color graph, progress indicator, disk analysis and fragmentation information being removed entirely.
If the fragments of a file are over 64 MB in size, the file is not defragmented if using the GUI; Microsoft has stated that this is because there is no discernible performance benefit since the time seeking such large chunks of data is negligible compared to the time required to read them. The result, however, is that ''Disk Defragmenter'' does not require a certain amount of free space in order to successfully defrag a volume, unlike performing a full defragmentation which requires at least 15% of free space on the volume. The command line utility, ''Defrag.exe'', offers more control over the defragmentation process, such as performing a full defragmentation by consolidating all file fragments regardless of size. This utility can be used to defragment specific volumes or to just analyze volumes as the defragmenter would in Windows XP
Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users a ...
.
Disk Defragmenter is maintained by Microsoft's Core File Services. The Windows Vista version has been updated in Windows Vista SP1 to include the improvements made in Windows Server 2008
Windows Server 2008, codenamed "Longhorn Server" (alternatives: "Windows Vista Server" or "Windows Server Vista"), is the seventh major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server b ...
. The most notable of these improvements is that the ability to select which volumes are to be defragmented has been added back.
Notably, the Windows Vista defragmenter is much more effective than the version included with XP.
Windows 7 and later
Windows 7
Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...
reintroduces the analyze function and showing percent complete of the defragmentation, both of which were removed in Windows Vista. It can also defragment multiple volumes simultaneously.
According to Scott Hanselman of Microsoft
Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...
, Windows 7 and later do defragment a solid-state disk
A solid-state drive (SSD) is a type of solid-state storage device that uses Integrated circuit, integrated circuits to store data persistence (computer science), persistently. It is sometimes called semiconductor storage device, solid-stat ...
(SSD) but in a completely different way. There is less incentive for defragmentation of SSDs because file fragmentation has less performance impact on them and they handle a finite number of storage cycles before their lifespan expires. However, file systems cannot support infinite file fragmentation as they reach their metadata limit. In addition, Microsoft Drive Optimizer is also responsible for performing the TRIM command on SSDs.
See also
* Defragmentation
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 ...
* File system fragmentation
In computing, file system fragmentation, sometimes called file system aging, is the tendency of a file system to lay out the contents of Computer file, files non-continuously to allow in-place modification of their contents. It is a special case of ...
* Comparison of defragmentation software
__NOTOC__
The following is a comparison of notable file system defragmentation software:
Notes
References
{{Reflist, 30em
External links
The Big Windows 7 Defragmenter TestThe Big Windows XP Defragmenter Test
Defragmentation softw ...
References
External links
Troubleshooting Microsoft Drive Optimizer
{{Windows Components
Windows components
Defragmentation software