Drive Letter Access (DLA) is a discontinued commercial

packet writing Packet writing (or incremental packet writing, IPW) is an optical disc recording technology used to allow write-once and rewritable CD and DVD media to be used in a similar manner to a floppy disk from within the operating system. Details P ...

application for the

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

operating system that allows

optical disc In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...

data storage device Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are conside ...

s to be used in a manner similar to

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent 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 w ...

s. DLA is a packet writing technology for CD and

DVD The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...

media that uses the UDF

file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...

. DLA is not compatible with Windows Vista and newer, although a patch exists to fix this issue under Windows Vista. Roxio Burn was introduced on April 30, 2009. As a replacement for DLA, it remedies compatibility issues

Internet Explorer 8 Windows Internet Explorer 8 (IE8) is a web browser for Windows. It was released by Microsoft on March 19, 2009, as the eighth version of Internet Explorer and the successor to Internet Explorer 7. It was the default browser in Windows 7 (later def ...

History

DLA was originally developed by

VERITAS Software Veritas Technologies LLC. is an American international data management company headquartered in Santa Clara, California. The company has its origins in Tolerant Systems, founded in 1983 and later renamed Veritas Software. It specializes in stor ...

and later sold to

Sonic Solutions Sonic Solutions was an American computer software company headquartered in Novato, California. In addition to having a number of offices in the U.S., the company also maintained offices in Europe and Asia. It was acquired by Rovi Corporation in 201 ...

in 2002. It was common as it was shipped with a majority of CD and DVD recording drives, where DLA came as a custom

OEM An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional or ...

version for the branded drive. Also, most PC systems from

Dell Dell is an American based technology company. It develops, sells, repairs, and supports computers and related products and services. Dell is owned by its parent company, Dell Technologies. Dell sells personal computers (PCs), servers, data ...

, HP, IBM,

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...

and

Toshiba , commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure system ...

came with DLA pre-installed. An OEM version was often available for download for the specific computer system. With Windows Vista support for DLA was either dropped or it was replaced by a similar product, like Drag-to-Disc.

Technology

To use an optical medium such as a CD-R, CD-RW, DVD±R or DVD±RW just like a floppy drive it is necessary to utilize a technique called packet writing. After formatting the optical media it is then possible to write data in small packets, hence the name “packet writing.” The optical drive unit has to support the ability to write in small units, which all modern CD and DVD recording drives do. This way it is possible to save files onto optical media, as well as change, rename or delete them, or copy files separately onto the media. Without packet writing, optical media like the above-mentioned would have to be written on in one big block, like Disc At Once (

DAO Dao, Dão or DAO may refer to: * Tao (Chinese: "The Way" 道), a philosophical concept * Dao (Chinese sword) (刀), a type of Chinese sword * Dao (Naga sword), a weapon and a tool of Naga people People and language * Yao people, a minority ethni ...

), Session At Once (

SAO SAO or Sao may refer to: Places * Sao civilisation, in Middle Africa from 6th century BC to 16th century AD * Sao, a town in Boussé Department, Burkina Faso * Saco Transportation Center (station code SAO), a train station in Saco, Maine, U.S. ...

) and Track At Once (

TAO ''Tao'' or ''Dao'' is the natural order of the universe, whose character one's intuition must discern to realize the potential for individual wisdom, as conceived in the context of East Asian philosophy, East Asian religions, or any other phil ...

), because these media types normally do not support sectors. After formatting with packet writing the medium is sectored in blocks that can be written to individually. The preferred file system is the

Universal Disk Format Universal Disk Format (UDF) is an open, vendor-neutral file system for computer data storage for a broad range of media. In practice, it has been most widely used for DVDs and newer optical disc formats, supplanting ISO 9660. Due to its design, ...

(UDF) in versions from 1.50 onward, which is also used by DLA. Packet writing is not required for writing

DVD-RAM DVD-RAM (DVD Random Access Memory) is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorders an ...

. DVD-RAM media are already sectored (which can be seen when looking at the surface of an empty DVD-RAM disc) and the

hardware logic Electronic hardware consists of interconnected electronic components which perform analog circuit, analog or Digital electronics, logic operations on received and locally stored information to produce as output or store resulting new information ...

of DVD-RAM capable drives supports sectored read/write operations as required by the DVD-RAM standard. However, for Windows up to 2000, DLA will also add support for DVD-RAM together with the UDF file system, for Windows XP DLA will only add the UDF support.
DLA also supports the

Mount Rainier Mount Rainier (), indigenously known as Tahoma, Tacoma, Tacobet, or təqʷubəʔ, is a large active stratovolcano in the Cascade Range of the Pacific Northwest, located in Mount Rainier National Park about south-southeast of Seattle. With a s ...

standard with MRW capable drives. For Windows up to XP DLA will provide this functionality as well as the UDF support. Windows XP is the first Windows operating system to support DVD-RAM. Windows Vista is the first Windows operating system to support full UDF functionality (UDF up to version 2.50, full support meaning read and write operations) and Mount Rainier.

Versions

DLA is available only for

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

s and only in the

English language English is a West Germanic language of the Indo-European language family, with its earliest forms spoken by the inhabitants of early medieval England. It is named after the Angles, one of the ancient Germanic peoples that migrated to the is ...

. * Version 4.95 runs on Windows 98SE, Me, NT 4.0, 2000 and XP. * Version 5.21 is the most recent version for Windows 98SE, Me, 2000 and XP. ''Note:'' Most OEM versions officially support only Windows 2000 and XP; however, DLA itself also runs on older versions of Windows, like Windows 98 Second Edition and Windows Me, as well as Windows NT 4.0. A patch is required for Windows Vista compatibility, but it only works on the retail or trial version. The one exception is the Dell OEM version, but instead of patching DLA it will simply install Drag-to-Disc as a replacement.

Known problems

* DLA is not compatible with Internet Explorer 8. * DLA can cause stop errors ( BSoD) on the Windows Server 2003 operating system. * DLA can lock up a Windows XP system when a rewritable (RW) disc is inserted. * DLA may prevent ejection of media from an optical drive. When this occurs, a solution is to restart the operating system. * DLA may prevent installation of a program distributed on a rewritable CD or DVD. A solution is to deactivate DLA as follows: #Launch

Windows Explorer File Explorer, previously known as Windows Explorer, is a file manager application that is included with releases of the Microsoft Windows operating system from Windows 95 onwards. It provides a graphical user interface for accessing the file ...

or open its My Computer component. #Select the RW drive. #Right click on the drive. #Click "Properties" #Click the "Hardware" tab #Deselect (uncheck) Use with DLA * DLA can block upgrade to Windows 7 on Vista systems where this is installed, and can be very difficult to uninstall.

References

External links