Universal Disc Format
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Universal Disc 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, it is very well suited to incremental updates on both recordable and (re)writable optical media. UDF was developed and maintained by the Optical Storage Technology Association (OSTA). In engineering terms, Universal Disk Format is a profile of the specification known as ISO/IEC 13346 and ECMA-167. Usage Normally, authoring software will master a UDF file system in a batch process and write it to optical media in a single pass. But when packet writing to rewritable media, such as CD-RW, UDF allows files to be created, deleted and changed on-disc just as a general-purpose filesystem would on removable media like floppy disks and flash drives. This is also possible on write-once media, such as CD-R, but in that case the space occupied b ...
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International Organization For Standardization
The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Article 3 of the ISO Statutes. ISO was founded on 23 February 1947, and (as of November 2022) it has published over 24,500 international standards covering almost all aspects of technology and manufacturing. It has 809 Technical committees and sub committees to take care of standards development. The organization develops and publishes standardization in all technical and nontechnical fields other than Electrical engineering, electrical and electronic engineering, which is handled by the International Electrotechnical Commission, IEC.Editors of Encyclopedia Britannica. 3 June 2021.International Organization for Standardization" ''Encyclopedia Britannica''. Retrieved 2022-04-26. It is headquartered in Geneva, Switzerland, and works in 167 coun ...
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Computer Data Storage
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but less expensive and larger options further away. Generally, the fast volatile technologies (which lose data when off power) are referred to as "memory", while slower persistent technologies are referred to as "storage". Even the first computer designs, Charles Babbage's Analytical Engine and Percy Ludgate's Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction was extended in the Von Neumann ...
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DVD Consortium
The DVD Forum is an international organization composed of hardware, software, media and production companies that use and develop the DVD and formerly HD DVD formats. It was initially known as the DVD Consortium when it was founded in 1995. History and mission The DVD Forum was created to facilitate the exchange of information and ideas about the DVD format, another evolution of the LaserDisc format, and to enable it to grow through technical improvement and innovation. The organization hopes to promote worldwide acceptance of DVD for entertainment, consumer electronics and information technology applications. Membership in the DVD Forum is open to any company or organization involved in DVD research, development, or manufacturing; software firms and other DVD users interested in developing the format are also encouraged to join. Forum members can support other formats in addition to DVD. The DVD Forum is responsible for the official DVD format specification. The group handle ...
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File System Permissions
Most file systems include attributes of files and directories that control the ability of users to read, change, navigate, and execute the contents of the file system. In some cases, menu options or functions may be made visible or hidden depending on a user's permission level; this kind of user interface is referred to as permission-driven. Two types of permissions are widely available: traditional Unix file system permissions and access-control lists (ACLs) which are capable of more specific control. File system variations The original File Allocation Table file system has a per-file all-user read-only attribute. NTFS implemented in Microsoft Windows NT and its derivatives, use ACLs to provide a complex set of permissions. OpenVMS uses a permission scheme similar to that of Unix. There are four categories (system, owner, group, and world) and four types of access permissions (Read, Write, Execute and Delete). The categories are not mutually disjoint: World includes Group ...
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CD-R
CD-R (Compact disc-recordable) is a digital optical disc storage format. A CD-R disc is a compact disc that can be written once and read arbitrarily many times. CD-R discs (CD-Rs) are readable by most CD readers manufactured prior to the introduction of CD-R, unlike CD-RW discs. History Originally named CD Write-Once (WO), the CD-R specification was first published in 1988 by Philips and Sony in the Orange Book, which consists of several parts that provide details of the CD-WO, CD-MO (Magneto-Optic), and later CD-RW (ReWritable). The latest editions have abandoned the use of the term "CD-WO" in favor of "CD-R", while "CD-MO" was rarely used. Written CD-Rs and CD-RWs are, in the aspect of low-level encoding and data format, fully compatible with the audio CD (''Red Book'' CD-DA) and data CD (''Yellow Book'' CD-ROM) standards. The Yellow Book standard for CD-ROM only specifies a high-level data format and refers to the Red Book for all physical format and low-level code ...
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USB Flash Drive
Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply ( interfacing) between computers, peripherals and other computers. A broad variety of USB hardware exists, including 14 different connector types, of which USB-C is the most recent and the only one not currently deprecated. First released in 1996, the USB standards are maintained by the USB Implementers Forum (USB-IF). The four generations of USB are: USB 1.''x'', USB 2.0, USB 3.''x'', and USB4. Overview USB was designed to standardize the connection of peripherals to personal computers, both to communicate with and to supply electric power. It has largely replaced interfaces such as serial ports and parallel ports, and has become commonplace on a wide range of devices. Examples of peripherals that are connected via USB include computer keyboards and mice, video cameras, printers, portable media ...
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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 with a fabric that removes dust particles from the spinning disk. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device. The first floppy disks, invented and made by IBM, had a disk diameter of . Subsequently, the 5¼-inch and then the 3½-inch became a ubiquitous form of data storage and transfer into the first years of the 21st century. 3½-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5¼-inch, 8-inch, and other-size floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks. Floppy disk ...
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Filesystem
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 Computer data storage, stored and retrieved. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. By separating the data into pieces and giving each piece a name, the data are easily isolated and identified. Taking its name from the way a paper-based data management system is named, each group of data is called a "Computer file, file". The structure and logic rules used to manage the groups of data and their names is called a "file system." There are many kinds of file systems, each with unique structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications. For example ...
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CD-RW
CD-RW (Compact Disc-Rewritable) is a digital optical disc storage format introduced in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written. CD-RWs, as opposed to CDs, require specialized readers that have sensitive laser optics. Consequently, CD-RWs cannot be read in many CD readers built prior to the introduction of CD-RW. CD-ROM drives with a "MultiRead" certification are compatible. CD-RWs must be erased or blanked before reuse. Erasure methods include full blanking where the entire surface of the disc is erased and fast blanking where only metadata areas, such as PMA, TOC and pregap, are cleared. Fast blanking is quicker and usually sufficient to allow rewriting the disc. Full blanking removes all traces of the previous data, and is often used for confidentiality purposes. CD-RWs can sustain fewer re-writes compared to other storage media (ca. 1,000 compared up to 100,000). Ideal use is for test discs (e.g. for CD authoring), temporary ba ...
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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 Packet writing allows users to create, modify, and delete files and directories on demand without the need to ''burn'' a whole disc. Packet writing technology achieves this by writing data in incremental blocks rather than in a single block. Deleting files and directories of a CD-R using packet writing technology does not recover the space occupied by these objects but, rather, they are simply marked as being deleted (making them effectively ''hidden''). Similarly, changes to files cause new instances to be created instead of replacing the original files. Because of this, the available space on a non-rewritable medium using packet writing technology will decrease every time its content is modified. The most common file system for packet ...
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Optical Disc Authoring Software
Optical disc authoring, including DVD and Blu-ray Disc authoring, is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto an optical disc (typically a compact disc or DVD). Process To burn an optical disc, one usually first creates an optical disc image with a full file system, of a type designed for the optical disc, in temporary storage such as a file in another file system on a disk drive. One may test the image on target devices using rewriteable media such as CD-RW, DVD±RW and BD-RE. Then, one copies the image to the disc (usually write-once media for hard distribution). Most optical disc authoring utilities create a disc image and copy it to the disc in one bundled operation, so that end-users often do not know the distinction between creating and burning. However, it is useful to know because creating the disc image is a time-consuming process, while copying the ...
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Profile (engineering)
In standardization, a profile is a subset internal to a specification. Aspects of a complex technical specification may necessarily have more than one interpretation, and there are probably many optional features. These aspects constitute a profile of the standard. Two implementations engineered from the same description may not interoperate due to having a different profile of the standard. Vendors can even ignore features that they view as unimportant, yet prevail in the long run. The use of profiles in these ways can force one interpretation, or create de facto standards from official standards. Engineers can design or procure by using a profile to ensure interoperability. For example, the International Standard Profile, ISP, is used by the ISO in their ISO ISP series of standards; in the context of OSI networking, Britain uses the UK-GOSIP profile and the US uses US-GOSIP; there are also various mobile profiles adopted by the W3C for web standards. In particular, implem ...
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