Computer monitor

A monitor or display (sometimes called a visual display unit) is a piece of electrical equipment which displays images generated by devices such as computers, without producing a permanent record. The monitor comprises the display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD), while older monitors use a cathode ray tube (CRT).

Scanner

Scanner may refer to a number of technological devices:

• Scanner (radio), for searching for and receiving radio broadcasts
• A rotating radar antenna
• Image scanner, which digitizes a two-dimensional image
• 3D scanner, which digitizes the three-dimensional shape of a real object
• Barcode reader, which reads the data encoded in a barcode
• Vulnerability scanner, a computer program that probes for weaknesses
• Lexical analyzer, a computer program
• Stepper, a part of the photolithography process
• An outside broadcast control vehicle
• An automotive electronic control unit diagnostic tool
• An automated spotlight
• Port scanner, in computer networking
• A biometric scanner, an electronic device with a sensor to read patterns or
images from faces, irises and finger pads to create a biological template.

In popular culture, scanner may refer to:

• Scanner (Band), a German speed metal band
• Scanner (Code Lyoko), a fictional teleportation device
• The stage name of British electronic musician Robin Rimbaud
• A floating enemy in the computer game Half Life 2
• Scanners Live in Vain, a science fiction short story by Cordwainer Smith
• A Scanner Darkly, a science fiction novel by Philip K. Dick.
• Scanners, a 1981 science fiction horror film

Keyboard

In computing, a keyboard is an input device, partially modeled after the typewriter keyboard, which uses an arrangement of buttons or keys, which act as mechanical levers or electronic switches. A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands.

In normal usage, the keyboard is used to type text and numbers into a word processor, text editor or other program. In a modern computer, the interpretation of keypresses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all keypresses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using special gaming keyboards, which can expedite frequently used keystroke combinations. A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine.

DVD-R

DVD-R is a DVD recordable format. A DVD-R typically has a storage capacity of 4.71 GB (or 4.38 GiB), although the capacity of the original standard developed by Pioneer was 3.95 GB (3.68 GiB). Both values are significantly larger than the storage capacity of its optical predecessor, the 700 MB CD-R – a DVD-R has 6.4 times the capacity of a CD-R. Pioneer has also developed an 8.54 GB dual layer version, DVD-R DL, which appeared on the market in 2005.

Data on a DVD-R cannot be changed, whereas a DVD-RW (DVD-rewritable) can be rewritten multiple (1000+) times. DVD-R(W) is one of three competing industry standard DVD recordable formats; the others are DVD+R(W) and DVD-RAM.

Floppy Disk

A floppy disk is a data storage medium that is composed of a disk of thin, flexible ("floppy") magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which is another term for a (nonremovable type of) hard disk drive. Invented by IBM, floppy disks in 8-inch (200 mm), 5¼-inch (133⅓ mm), and the newest and most common 3½-inch (90 mm) formats enjoyed many years as a popular and ubiquitous form of data storage and exchange, from the mid-1970s to the late 1990s. While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have now been largely superseded by USB flash drives, External Hard Drives, CD-ROMs and DVD-ROMs.

DVD-RW

A DVD-RW disc is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. Unlike DVD-RAM, it is playable in about 75% of conventional DVD players.[citation needed] The smaller Mini DVD-RW holds 1.46 GB, with a diameter of 8 cm.

The primary advantage of DVD-RW over DVD-R is the ability to erase and rewrite to a DVD-RW disc. According to Pioneer, DVD-RW discs may be written to about 1,000 times before needing replacement, making them comparable with the CD-RW standard. DVD-RW discs are commonly used for volatile data, such as backups or collections of files. They are also increasingly used for home DVD video recorders. One benefit to using a rewritable disc is if there are writing errors when recording data, the disc is not ruined and can still store data by erasing the faulty data.

One competing rewritable format is DVD+RW. Hybrid drives that can handle both, often labeled "DVD±RW", are very popular due to the lack of a single standard for recordable DVDs.

The recording layer in DVD-RW and DVD+RW is not an organic dye, but a special phase change metal alloy, often GeSbTe. The alloy can be switched back and forth between a crystalline phase and an amorphous phase, changing the reflectivity, depending on the power of the laser beam. Data can thus be written, erased and re-written.

There is now a new format called DVD-RW2. Older DVD burners are not all forward compatible with this new standard.

The current fastest speed a DVD-RW disc can be written to is 6x speed, with many at this speed having DVD-RW2 capabilities.

DVD-ROM

DVD, also known as "Digital Versatile Disc" or "Digital Video Disc," is an optical disc storage media format. Its main uses are video and data storage. Most DVDs are of the same dimensions as compact discs (CDs) but store more than six times as much data.

Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM (Read Only Memory), has data that can only be read and not written, DVD-R and DVD+R can record data only once and then function as a DVD-ROM. DVD-RW, DVD+RW and DVD-RAM can both record and erase data multiple times. The wavelength used by standard DVD lasers is 650 nm,[1] and thus the light has a red color.

DVD-Video and DVD-Audio discs respectively refer to properly formatted and structured video and audio content. Other types of DVDs, including those with video content, may be referred to as DVD-Data discs. As next generation high-definition optical formats also use a disc identical in some aspects yet more advanced than a DVD, such as Blu-ray Disc, the original DVD is occasionally given the retronym SD DVD (for standard definition).