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Magnasee is a product used to visualize the magnetic fields recorded onto magnetic recording media such as magnetic tape, diskettes, and the like.
Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Only a few substances are ferromagnetic; the most common ones are iron, cobalt and nickel and their alloys such as steel. The prefix ferro- refers to iron, because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe3O4.
Magnetic tape is a medium for magnetic recording, made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders respectively. A device that stores computer data on magnetic tape is known as a tape drive.
A floppy disk, also known as a floppy, diskette, or simply disk, is a type of disk storage composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic enclosure lined with fabric that removes dust particles. Floppy disks are read and written by a floppy disk drive (FDD).
The product contains very fine colloidal iron in a fast-evaporating liquid such as naphtha or fluorocarbons. The liquid is first agitated vigorously to disperse the iron. It may then be carefully poured over the magnetic media of, in the case of tape, the tape may be dipped into the open container of liquid. The iron adheres between the magnetic domains of the media, allowing the user to see where these magnetic domains have been written. Allowing the carrier liquid to evaporate allows very close visualization of the domains.
Iron is a chemical element with symbol Fe and atomic number 26. It is a metal, that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust.
Naphtha is a flammable liquid hydrocarbon mixture.
Fluorocarbons, sometimes referred to as perfluorocarbons or PFCs, are, strictly speaking, organofluorine compounds with the formula CxFy, i.e. they contain only carbon and fluorine, though the terminology is not strictly followed. Compounds with the prefix perfluoro- are hydrocarbons, including those with heteroatoms, wherein all C-H bonds have been replaced by C-F bonds. Fluorocarbons can be perfluoroalkanes, fluoroalkenes and fluoroalkynes and perfluoroaromatic compounds. Fluorocarbons and their derivatives are used as fluoropolymers, refrigerants, solvents, and anesthetics.
Various faults in the magnetic recording process could then be visually detected. These included:[ citation needed ]
An azimuth is an angular measurement in a spherical coordinate system. The vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane; the angle between the projected vector and a reference vector on the reference plane is called the azimuth.
For many older systems that recorded at a low linear bit density, the bit density of the recording could be determined.
While Magnasee was most commonly used on magnetic media that wasn't meant to be re-used (for reading or writing), careful cleaning could remove the iron particles and allow critical media to be re-used.
Disk storage is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is a device implementing such a storage mechanism. Notable types are the hard disk drive (HDD) containing a non-removable disk, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives (ODD) and associated optical disc media.
A hard disk drive (HDD), hard disk, hard drive, or fixed disk, is an electro-mechanical data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially. HDDs are a type of non-volatile storage, retaining stored data even when powered off.
A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and a long archival stability.
Digital Audio Tape is a signal recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to a Compact Cassette, using 3.81 mm / 0.15" magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. As the name suggests, the recording is digital rather than analog. DAT has the ability to record at sampling rates equal to, as well as higher and lower than a CD at 16 bits quantization. If a comparable digital source is copied without returning to the analogue domain, then the DAT will produce an exact clone, unlike other digital media such as Digital Compact Cassette or non-Hi-MD MiniDisc, both of which use a lossy data reduction system.
An audio tape recorder, tape deck, or tape machine is a sound recording and reproduction device that records and plays back sounds usually using magnetic tape for storage. In its present-day form, it records a fluctuating signal by moving the tape across a tape head that polarizes the magnetic domains in the tape in proportion to the audio signal. Tape-recording devices include the reel-to-reel tape deck and the cassette deck, which uses a cassette for storage.
Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetized areas, known as bubbles or domains, each storing one bit of data. The material is arranged to form a series of parallel tracks that the bubbles can move along under the action of an external magnetic field. The bubbles are read by moving them to the edge of the material where they can be read by a conventional magnetic pickup, and then rewritten on the far edge to keep the memory cycling through the material. In operation, bubble memories are similar to delay line memory systems.
A magnetic stripe card is a type of card capable of storing data by modifying the magnetism of tiny iron-based magnetic particles on a band of magnetic material on the card. The magnetic stripe, sometimes called swipe card or magstripe, is read by swiping past a magnetic reading head. Magnetic stripe cards are commonly used in credit cards, identity cards, and transportation tickets. They may also contain an RFID tag, a transponder device and/or a microchip mostly used for business premises access control or electronic payment.
Video editing is the manipulation and arrangement of video shots. Video editing is used to structure and present all video information, including films and television shows, video advertisements and video essays. Video editing has been dramatically democratized in recent years by editing software available for personal computers.
Mastering, a form of audio post production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device, the source from which all copies will be produced. In recent years digital masters have become usual, although analog masters, such as audio tapes, are still being used by the manufacturing industry, notably by a few engineers who have chosen to specialize in analog mastering.
Reel-to-reel or open-reel audio tape recording is a form of magnetic tape audio recording in which the recording medium is held on a reel, rather than being securely contained within a cassette. In use, the supply reel or feed reel containing the tape is mounted on a spindle; the end of the tape is manually pulled out of the reel, threaded through mechanical guides and a tape head assembly, and attached by friction to the hub of a second, initially empty takeup reel.
In computer science, group coded recording or group code recording (GCR) refers to several distinct but related encoding methods for magnetic media. The first, used in 6250 bpi magnetic tape since 1973, is an error-correcting code combined with a run length limited (RLL) encoding scheme, belonging into the group of modulation codes. The others are different mainframe hard disk as well as floppy disk encoding methods used in some microcomputers until the late 1980s. GCR is a modified form of a NRZI code, but necessarily with a higher transition density.
DECtape is a magnetic tape data storage medium used with many Digital Equipment Corporation computers, including the PDP-6, PDP-8, LINC-8, PDP-9, PDP-10, PDP-11, PDP-12, and the PDP-15. On DEC's 32-bit systems, VAX/VMS support for it was implemented but did not become an official part of the product lineup.
Magnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetisable material to store data and is a form of non-volatile memory. The information is accessed using one or more read/write heads.
The 8mm video format refers informally to three related videocassette formats for the NTSC and PAL/SECAM television systems. These are the original Video8 format and its improved successor Hi8, as well as a more recent digital recording format known as Digital8.
Areal density is a measure of the quantity of information bits that can be stored on a given length of track, area of surface, or in a given volume of a computer storage medium. Generally, higher density is more desirable, for it allows more data to be stored in the same physical space. Density therefore has a direct relationship to storage capacity of a given medium. Density also generally affects the performance within a particular medium, as well as price.
The history of sound recording - which has progressed in waves, driven by the invention and commercial introduction of new technologies — can be roughly divided into four main periods:
IBM's first magnetic tape data storage devices, introduced in 1952, use what is now generally known as 7 track tape. The magnetic tape is 1/2" wide and there are six data tracks plus one parity track for a total of seven parallel tracks that span the length of the tape. Data is stored as six-bit characters, with each bit of the character and the additional parity bit stored in a different track.
The IBM System/360, released in 1964, introduced what is now generally known as 9 track tape. The ½ inch (12.7 mm) wide magnetic tape media and reels are the same size as the earlier IBM 7 track format it replaced, but the new format has eight data tracks and one parity track for a total of nine parallel tracks. Data is stored as 8-bit characters, spanning the full width of the tape. Various recording methods were employed during its lifetime as tape speed and data density increased, including PE, GCR and NRZI. Tapes came in various sizes up to 3,600 feet (1,100 m) in length.
Magnetic tape data storage is a system for storing digital information on magnetic tape using digital recording. Modern magnetic tape is most commonly packaged in cartridges and cassettes. The device that performs writing or reading of data is a tape drive. Autoloaders and tape libraries automate cartridge handling. For example, a common cassette-based format is Linear Tape-Open, which comes in a variety of densities and is manufactured by several companies.
The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.