Difference Between Magnetic Storage And Optical Storage Pdf


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difference between magnetic storage and optical storage pdf

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Optical storage , electronic storage medium that uses low-power laser beams to record and retrieve digital binary data.

Recovery and from the device which are the most actively used to perform the years optical disc.

Difference Between Optic Disk And Magnetic Disk (With Comparison Chart)

Magnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetizable material to store data and is a form of non-volatile memory. Magnetic storage media, primarily hard disks , are widely used to store computer data as well as audio and video signals. In the field of computing, the term magnetic storage is preferred and in the field of audio and video production, the term magnetic recording is more commonly used.

The distinction is less technical and more a matter of preference. Other examples of magnetic storage media include floppy disks , magnetic tape , and magnetic stripes on credit cards.

Magnetic storage in the form of wire recording —audio recording on a wire—was publicized by Oberlin Smith in the Sept 8, issue of Electrical World. The first publicly demonstrated Paris Exposition of magnetic recorder was invented by Valdemar Poulsen in Poulsen's device recorded a signal on a wire wrapped around a drum. In , Fritz Pfleumer developed the first magnetic tape recorder. Early magnetic storage devices were designed to record analog audio signals.

Computers and now most audio and video magnetic storage devices record digital data. In old 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. Unlike modern computers, magnetic tape was also often used for secondary storage. Information is written to and read from the storage medium as it moves past devices called read-and-write heads that operate very close often tens of nanometers over the magnetic surface.

The read-and-write head is used to detect and modify the magnetisation of the material immediately under it. There are two magnetic polarities, each of which is used to represent either 0 or 1. The magnetic surface is conceptually divided into many small sub- micrometer -sized magnetic regions, referred to as magnetic domains, although these are not magnetic domains in a rigorous physical sense , each of which has a mostly uniform magnetisation.

Due to the polycrystalline nature of the magnetic material each of these magnetic regions is composed of a few hundred magnetic grains. Each magnetic region in total forms a magnetic dipole which generates a magnetic field. In older hard disk drive HDD designs the regions were oriented horizontally and parallel to the disk surface, but beginning about , the orientation was changed to perpendicular to allow for closer magnetic domain spacing [ citation needed ].

Older hard disk drives used iron III oxide Fe 2 O 3 as the magnetic material, but current disks use a cobalt -based alloy. For reliable storage of data, the recording material needs to resist self-demagnetisation, which occurs when the magnetic domains repel each other. Magnetic domains written too close together in a weakly magnetisable material will degrade over time due to rotation of the magnetic moment of one or more domains to cancel out these forces.

The domains rotate sideways to a halfway position that weakens the readability of the domain and relieves the magnetic stresses. A write head magnetises a region by generating a strong local magnetic field, and a read head detects the magnetisation of the regions. Early HDDs used an electromagnet both to magnetise the region and to then read its magnetic field by using electromagnetic induction. As data density increased, read heads using magnetoresistance MR came into use; the electrical resistance of the head changed according to the strength of the magnetism from the platter.

Later development made use of spintronics ; in read heads, the magnetoresistive effect was much greater than in earlier types, and was dubbed "giant" magnetoresistance GMR. In today's heads, the read and write elements are separate, but in close proximity, on the head portion of an actuator arm. The read element is typically magneto-resistive while the write element is typically thin-film inductive. The heads are kept from contacting the platter surface by the air that is extremely close to the platter; that air moves at or near the platter speed.

The record and playback head are mounted on a block called a slider, and the surface next to the platter is shaped to keep it just barely out of contact. This forms a type of air bearing. Analog recording is based on the fact that remnant magnetisation of a given material depends on the magnitude of the applied field. The magnetic material is normally in the form of tape, with the tape in its blank form being initially demagnetised.

When recording, the tape runs at a constant speed. The writing head magnetises the tape with current proportional to the signal. A magnetisation distribution is achieved along the magnetic tape. Finally, the distribution of the magnetisation can be read out, reproducing the original signal.

The magnetic tape is typically made by embedding magnetic particles approximately 0. The most commonly-used of these was ferric oxide, though chromium dioxide, cobalt, and later pure metal particles were also used.

Analog recording was the most popular method of audio and video recording. Since the late s, however, tape recording has declined in popularity due to digital recording.

Examples of digital recording are floppy disks and hard disk drives HDDs. Digital recording has also been carried out on tapes. When writing, the magnetic medium is heated locally by a laser , which induces a rapid decrease of coercive field. Then, a small magnetic field can be used to switch the magnetisation. The reading process is based on magneto-optical Kerr effect. The magnetic medium are typically amorphous R-Fe-Co thin film R being a rare earth element.

Magneto-optical recording is not very popular. One famous example is Minidisc developed by Sony. Domain propagation memory is also called bubble memory. The basic idea is to control domain wall motion in a magnetic medium that is free of microstructure. Bubble refers to a stable cylindrical domain. Domain propagation memory has high insensitivity to shock and vibration, so its application is usually in space and aeronautics. Magnetic storage media can be classified as either sequential access memory or random access memory , although in some cases the distinction is not perfectly clear.

The access time can be defined as the average time needed to gain access to stored records. Accessing different parts of the wire involves winding the wire forward or backward until the point of interest is found. The time to access this point depends on how far away it is from the starting point. The case of ferrite-core memory is the opposite. Every core location is immediately accessible at any given time.

Hard disks and modern linear serpentine tape drives do not precisely fit into either category. Different spots on the storage media take different amounts of time to access. For a hard disk this time is typically less than 10 ms, but tapes might take as much as s.

Magnetic disk heads and magnetic tape heads cannot pass DC direct current. So the coding schemes for both tape and disk data are designed to minimize the DC offset.

Many magnetic disks internally use some form of run-length limited coding and partial-response maximum-likelihood. As of [update] , 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 analog 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.

Digital tape and tape libraries are popular for the high capacity data storage of archives and backups. Floppy disks see some marginal usage, particularly in dealing with older computer systems and software. A new type of magnetic storage, called magnetoresistive random-access memory or MRAM, is being produced that stores data in magnetic bits based on the tunnel magnetoresistance TMR effect. Its advantage is non-volatility, low power usage, and good shock robustness.

The 1st generation that was developed was produced by Everspin Technologies , and utilized field induced writing. Research is also being done by Aleksei Kimel at Radboud University [12] towards the possibility of using terahertz radiation rather than using standard electropulses for writing data on magnetic storage media.

By using terahertz radiation, writing time can be reduced considerably 50x faster then when using standard electropulses. Another advantage is that terahertz radiation generates almost no heat, thus reducing cooling requirements. From Wikipedia, the free encyclopedia.

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. The storage of data in a magnetizable medium through encoded patterns of magnetization.

Main article: Magnetic tape sound recording. For Your Information. Galaxy Science Fiction. Retrieved 24 June Archived from the original on Retrieved 4 September Retrieved Gignoux, and M. Piramanayagam and Tow C. Archived from the original PDF on EE Times. Magnetic storage media. Categories : American inventions Storage media Computer storage media Magnetic devices. Hidden categories: Webarchive template wayback links CS1 maint: archived copy as title Articles needing additional references from October All articles needing additional references Articles with short description Short description is different from Wikidata All articles with unsourced statements Articles with unsourced statements from November Articles containing potentially dated statements from All articles containing potentially dated statements Articles with unsourced statements from March Wikipedia articles with BNE identifiers Wikipedia articles with BNF identifiers Wikipedia articles with GND identifiers Wikipedia articles with LCCN identifiers Wikipedia articles with NDL identifiers Wikipedia articles with multiple identifiers.

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Optical storage

Optical storage is the storage of data on an optically readable medium. Data is recorded by making marks in a pattern that can be read back with the aid of light, often a beam of light focused on a spinning optical disk. Therefore, an optic disk is any computer disk that uses optical storage techniques and technology to read and write data. They are generally used as a portable and secondary storage device. Optical disks are commonly used to:.

Data storage is the recording storing of information data in a storage medium. Handwriting, phonographic recording, magnetic tape , and optical discs are all examples of storage media, some authors even propose that DNA is a natural data storage mechanism. Electronic data storage requires electrical power to store and retrieve data. Data storage in a digital, machine-readable medium is sometimes called digital data. Computer data storage is one of the core functions of a general-purpose computer.

Difference between Magnetic Disk and Optical Disk

Differences between optical and magnetic storage devices are how they store and retrieve data. Both devices are used for long term data storage. Online Class Notes, your source for class notes of different course of computer science and technology degree. Learn More. Skip to content.

The Magnetic disk and Optical disk are the storage devices provides a way to store data for a long duration. These disks differ in many characteristics; firstly magnetic disk works by using magnetising material over the disk whereas in optical disk polycarbonate plastic is used in its construction and laser is used to store and retrieve the data. The magnetic and optical disk comes under the category of secondary storage devices.

Discuss the comparison in terms of technical aspects and give example for each:. Magnetic Storage Devices: Magnetic storage is one of the most affordable ways to store large amounts of data. Magnetic storage uses the two types of magnetic polarities to represent the binary information consisting of zeros and ones. Commonly used devices that use magnetic storage include magnetic tape, floppy disks and hard-disk drives.

Difference between Magnetic and Optical Storage

Magnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetizable material to store data and is a form of non-volatile memory.

Content: Magnetic disk and Optical disk

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8 Differences between optical and magnetic storage devices.

2 Comments

VГ©ronique C.
04.12.2020 at 22:45 - Reply

devices use "read/write heads," electromagnets that detect (read) or change (write) the magnetization patterns on the.

Victoria Q.
09.12.2020 at 07:30 - Reply

Optical storage devices are flat, round disks which spins around its center. The difference with magnetic storage devices is that in optical storage devices LASER light is used to read and write data in disks. Examples are CD, DVD etc.

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