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Encyclopedia > Magnetic tape
Compact audio cassette
Compact audio cassette

Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. Nearly all recording tape is of this type, whether used for video, audio storage or general purpose digital data storage using a computer. Download high resolution version (800x619, 67 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (800x619, 67 KB) Wikipedia does not have an article with this exact name. ... Non-volatile memory, or non-volatile storage, is computer memory that can retain the stored information even when not powered. ... The terms storage (U.K.) or memory (U.S.) refer to the parts of a digital computer that retain physical state (data) for some interval of time, possibly even after electrical power to the computer is turned off. ... Household items made out of plastic. ... Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images which represent scenes in motion. ... Audio storage refers to techniques and formats used to store audio with the goal to reproduce the audio later using audio signal processing to something that resembles the original. ... A BlueGene supercomputer cabinet. ...


Magneto-optical and optical tape storage products have been developed using many of the same concepts as magnetic storage, but have achieved little commercial success. Magnetic storage is a term from engineering referring to the storage of data on a magnetised medium. ...

Contents

Audio recording

7 inch reel of ¼ inch-wide recording tape, typical of consumer use in the 1950s-70s.
7 inch reel of ¼ inch-wide recording tape, typical of consumer use in the 1950s-70s.

Magnetic tape was first invented for recording sound by Fritz Pfleumer in 1926 in Germany, based on the invention of magnetic wire recording by Valdemar Poulsen in 1898. Pfleumer's invention used an oxide powder coating on a long strip of paper. This invention was further developed by the German electronics company AEG, which manufactured the recording machines and BASF, which manufactured the tape. An important discovery made in this period was the technique of AC biasing which dramatically improved the fidelity of the recorded audio signal. Picture of a 7-1/2 reel of magnetic recording tape, as used in the mid-1960s Image by Daniel P. B. Smith. ... Picture of a 7-1/2 reel of magnetic recording tape, as used in the mid-1960s Image by Daniel P. B. Smith. ... Fritz Pfleumer (20 March 1881 in Salzburg - 29 August 1945 in Radebeul) was a German engineer and inventor of magnetic tape. ... Year 1926 (MCMXXVI) was a common year starting on Friday (link will display the full calendar). ... Wire recording is a type of analogue audio storage in which the recording is made onto thin steel or stainless steel wire. ... Valdemar Poulsen (1869 - 1942) was a Danish engineer. ... 1898 (MDCCCXCVIII) was a common year starting on Saturday (see link for calendar) of the Gregorian calendar (or a common year starting on Monday of the 12-day-slower Julian calendar). ... AEG volt-metre designed by Peter Behrens AEG (Allgemeine Elektrizitäts-Gesellschaft) (English Translation: General Electricity Company) was a German producer of electronics and electrical equipment. ... BASF may also historically refer to EMTEC, which was known as BASF for a short time after its founding. ... Tape bias is a high-frequency signal (generally from 40 to 150 kHz) added to the audio signal recorded on an analog tape recorder. ...


Due to the international hostilities preceding World War II, these developments were largely kept secret from the rest of the world. It was only after the war that Americans, particularly Jack Mullin and Major John Herbert Orr, were able to bring this technology out of Germany. Combatants Allied Powers: United Kingdom France Soviet Union United States Republic of China and others Axis Powers: Germany Italy Japan and others Commanders Winston Churchill Charles de Gaulle Joseph Stalin Franklin Roosevelt Chiang Kai-Shek Adolf Hitler Benito Mussolini Hideki Tojo Casualties Military dead: 17,000,000 Civilian dead: 33... John T. Jack Mullin (1913–1999) was an American pioneer in the field of electronic audio and video recording using magnetic tape. ... There are very few or no other articles that link to this one. ...


A wide variety of recorders and formats have developed since.


See also

Methods and media for sound recording are varied and have undergone significant changes between the first time sound was actually recorded for later playback until now. ... A U.S. Postage Stamp commemorating one hundred years of sound recording. ... Audio storage refers to techniques and formats used to store audio with the goal to reproduce the audio later using audio signal processing to something that resembles the original. ... It has been suggested that this article or section be merged with audio storage. ... Since the widespread adoption of reel-to-reel audio tape recording in the 1950s, audio tapes and tape cassettes have been available in many formats. ... Sony reel-to-reel tape recorder. ... A reel-to-reel tape recorder (Sony TC-630), typical of those which were once common audiophile objects. ... The Tascam 85 16B analogue tape recorder can record 16 tracks of audio on 1 inch (2. ...

Video recording

Main article: Videotape

Video recording demands much higher bandwidth than audio recording and was made practical by the invention of helical scan. Early video recorders were reel-to-reel but modern systems use cartridge tapes and videocassette recorders are very common in homes and television production facilities, though many functions of the VCR are being replaced by optical disc media. Bottom view of VHS videotape cassette with magnetic tape exposed Videotape is a means of recording television pictures and accompanying sound onto magnetic tape as opposed to movie film. ... This article or section does not cite its references or sources. ... The head drum of a Hi-Fi NTSC VHS VCR; three of the six heads face the reader. ... The videocassette recorder (or VCR, more commonly known in the British Isles as the video recorder), is a type of video tape recorder that uses removable videotape cassettes containing magnetic tape to record audio and video from a television broadcast so it can be played back later. ... The optical lens of a compact disc drive. ...


Data storage

The use of magnetic tape for data storage has been one of the constants of the computer industry. Magnetic tape has been used for data storage for over 50 years. ... The terms storage (U.K.) or memory (U.S.) refer to the parts of a digital computer that retain physical state (data) for some interval of time, possibly even after electrical power to the computer is turned off. ...


Magnetic tape was first used to record computer data in 1951 on the Eckert-Mauchly UNIVAC I. The recording medium was a strip of ½″ (12.7 mm) wide thin metal, consisting of nickel-plated bronze (called Vicalloy). Recording density was 128 characters per inch (198 micrometre/character) on eight tracks at a linear speed of 100 in/s (2.54 m/s), yielding a data rate of 12,800 characters per second. Of the eight tracks, six were data, one was a parity track, and one was a clock, or timing track. Making allowance for the empty space between tape blocks, the actual transfer rate was around 7,200 characters per second. UNIVAC I Central Complex, containing the central processor and main memory unit. ... A parity bit is a binary digit that indicates whether the number of bits with value of one in a given set of bits is even or odd. ...

Small open reel showing the Beginning-Of-Tape reflective marker.
Small open reel showing the Beginning-Of-Tape reflective marker.

Early IBM tape drives were mechanically sophisticated floor-standing drives that used vacuum columns to buffer long u-shaped loops of tape. Between active control of powerful reel motors and vacuum control of these u-shaped tape loops, extremely rapid start and stop of the tape at the tape-to-head interface could be achieved. (1.5ms from stopped tape to full speed of up to 112.5 IPS) When active, the two tape reels thus fed tape into or pulled tape out of the vacuum columns, intermittently spinning in rapid, unsynchronized bursts resulting in visually-striking action. Stock shots of such vacuum-column tape drives in motion were widely used to represent "the computer" in movies and television. Image File history File linksMetadata Download high resolution version (2178x1230, 300 KB) Title : A 1/2 computer tape and the start-of-data sticker. ... Image File history File linksMetadata Download high resolution version (2178x1230, 300 KB) Title : A 1/2 computer tape and the start-of-data sticker. ...

Quarter-Inch cartridges.
Quarter-Inch cartridges.

Most late 1970's and early 1980's home computers used compact audio cassettes encoded with the Kansas City standard. Image File history File links Download high resolution version (970x661, 114 KB) Beschreibung: Zwei verschiedene Quarter-Inch Cartridges. ... Image File history File links Download high resolution version (970x661, 114 KB) Beschreibung: Zwei verschiedene Quarter-Inch Cartridges. ... The home computer is a consumer-friendly word for the second generation of microcomputers (the technical term that was previously used), entering the market in 1977 and becoming common during the 1980s. ... The Kansas City standard (abbreviated KCS) for storage of digital (micro)computer data on an ordinary compact audio cassette is also known as the BYTE standard, from its connection with BYTE magazine, or the Processor Technology CUTS (PT Computer Users Tape Standard). ...


Most modern magnetic tape systems use reels that are much smaller than the old 10.5 inch open reels and are fixed inside a cartridge to protect the tape and facilitate handling. A tape drive (or "transport" or "deck") uses precisely-controlled motors to wind the tape from one reel to the other, passing a read/write head as it does. Modern cartridge formats include DAT/DDC, AIT, DLT and LTO. Digital Data Storage (DDS) is a format for storing and backing up computer data on magnetic tape that evolved from Digital Audio Tape (DAT) technology, which was originally created for CD-quality audio recording. ... Advanced Intelligent Tape (AIT) is a computer storage magnetic tape format developed by Sony. ... A Super DLT I tape cartridge Digital Linear Tape (DLT) is considered a de facto standard for magnetic tape technology used for computer data storage. ... Linear Tape-Open (or LTO) is a magnetic tape data storage technology developed as an open alternative to the proprietary Digital Linear Tape (DLT). ...


Tape has quite a long data latency for random accesses since the deck must wind an average of ⅓ the tape length to move from one arbitrary data block to another. Most tape systems attempt to alleviate the intrinsic long latency, either using indexing, where a separate lookup table is maintained which gives the physical tape location for a given data block number, or by marking blocks with a tape mark that can be detected while winding the tape at high speed.


Tape remains a viable alternative to disk due to its lower cost per bit. Though the areal density is lower than for disk drives, the available surface on a tape is far greater. The highest capacity tape media are generally on the same order as the largest available disk drives (about 1 TB in 2007.) Tape has historically offered enough advantage in cost over disk storage to make it a viable product, particularly for backup, where media removability is also important. The rapid improvement in disk storage density and price, coupled with arguably less-vigorous innovation in tape storage, has reduced the market share of tape storage products. A terabyte (derived from the prefix tera-) is a measurement term for data storage capacity equal to 1000 gigabytes, i. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...


References

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. The Free On-line Dictionary of Computing (FOLDOC) is an online, searchable encyclopedic dictionary of computing subjects. ... GNU logo (similar in appearance to a gnu) The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free content, designed by the Free Software Foundation (FSF) for the GNU project. ...


  Results from FactBites:
 
magnetic tape - Magnum Magnetics (199 words)
Magnetic tape is a permanent flexible magnetic material available in strip and extrusion forms; standard or custom manufactured to satisfy specific processing requirements.
Magnetic tape is available with a variety of surfaces including adhesive.
Magnetic tape is used for fastening devices; displays; assembly devices; advertising specialties; hobbies; nameplates; printing; crafts; novelties; message boards; P.O.P. displays; instruction boards; exhibit booths; menu boards; craft displays; schedule boards; surface-mount signs; planning boards; floor signs; doodle boards; toys; games; bin markers; display boards; graphics; hand lettering; hot stamping; teaching aids; and reminders.
ANSDIT - The letter "M" (2158 words)
A magnetic storage in which data are magnetically recorded on the surface of a magnetic drum that rotates on its axis when in use.
The portion of magnetic tape that precedes the beginning-of-tape marker.
A magnetic storage in which data are magnetically recorded on the surface of a tape that moves longitudinally when in use.
  More results at FactBites »

 
 

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