Magnetic storage
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Magnetic storage is a term from engineering referring to the storage of data on a magnetised medium. Magnetic storage uses different patterns of magnetization on a magnetically coated surface to store data and is non-volatile. The information is accessed using one or more read/write heads. Since the read/write head only covers a part of the surface, magnetic storage is sequential access and must seek, cycle or both. As of 2006, magnetic storage media, primarily hard disks and tape cartridges, are widely used to store computer data as well as audio and video signals.
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[edit] History
Magnetic storage was first suggested by Oberlin Smith in 1888. The first working magnetic recorder was invented by Valdemar Poulsen in 1898. Poulsen's device recorded a signal on a wire wrapped around a drum. In 1928, Fritz Pfleumer developed the first magnetic tape recorder. Early magnetic storage devices were designed to record analog audio signals. Modern magnetic storage devices are designed for recording digital data.
In early computers, magnetic storage was also used for primary storage in a form of magnetic drum, or core memory, core rope memory, thin film memory, twistor memory or bubble memory. Also unlike modern computers, magnetic tape was often used for secondary storage.
[edit] Current usage
As of 2006, the most common uses of magnetic storage media are for computer data mass storage on hard disks and the recording of analog audio and video works on tape. Since much of audio and video production is moving to digital systems, the usage of hard disks is expected to increase at the expense of analog tape. Conversely, recent advances in tape cartridge capacity and tape library robotics have made tape more popular for the high capacity data storage requirements of archives and backups. Floppy disks still see some limited usage, particularly in dealing with older computer systems and software.
[edit] Future
A new type of magnetic storage, called MRAM, is being produced that stores data in magnetic bits based on the GMR effect. Its advantage is non-volatility, low power usage, and good shock robustness. However, with storage density and capacity orders of magnitude smaller than e.g. an HDD, MRAM is a niche application for situations where small amounts of storage with a need for very frequent updates (>10**15 writes) are required, which Flash Memory memory could not support.
[edit] See Also
- Data Storage - A broader perspective.
- Magnetism - The phenomenon.
- Magnetization - The property of an object that is affected by magnetism.
