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The Magnetic Storage Devices Computer Science Essay

The magnetic storage devices have been playing an of import function in our life. Magnetic storage is a device to hive away informations and its non-volatile memory. Magnetic storage can be classified as either consecutive entree memory or random entree memory. Most common used magnetic storage is Difficult Drive, Floppy Disk, MRAM, Magnetic Stripe Card, Drum Memory, and many more. There are many magnetic storage was invented but in this scrapbook is merely wrote about the Hard Drive, MRAM, Floppy Disk, and the Magnetic Stripe Card merely.

Difficult disc thrust is a non-volatile storage device which shops digitally encoded information on quickly revolving platters with magnetic surface, it normally referred to as difficult thrust, difficult disc, or fixed disc thrust. Early difficult disc thrust had removable media, nevertheless, a difficult disc thrust today typically a certain unit with fixed media. Hard disc thrust was introduced in September 13, 1956 as informations storage for an IBM accounting computing machine and it was originally developed for usage with general purpose computing machines.

In the twenty-first century, application for difficult disc thrust has expanded to include digital picture recording equipments, digital sound participants, personal digital helper, digital camera and picture game consoles. Most difficult thrusts are for good stored in an internal thrust bay at the forepart of the computing machine and are connected with one ATA / SCSI overseas telegram and power overseas telegram.

A difficult disc thrust

Technology of Hard Disk Drive

Difficult disc thrust record informations by magnetising ferromagnetic stuff directionally to stand for either a 0 or 1 binary figure.

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It read the informations back by observing the magnetisation of the stuff. A typical difficult disc thrust design consists of a spindle which holds one or more level round disc called platters, onto which the informations are recorded. The platters are made from a non-magnetic stuff. Normally aluminium metal or glass, and are coated with a think bed of magnetic stuff. Older disc used Fe ( III ) oxide as the magnetic stuff, but current disc usage a cobalt-based metal.

The platter are spun at really high velocities. The information to a platter as it rotates past devices called read-and-write caputs that operate really near over the magnetic surface. The read-and-write caput is used to observe and modify the magnetisation of the stuff instantly under it. For each platter surface on the spindle there is one caput.

The older difficult disc thrust read informations on the latter by feeling the rate of alteration of the magnetic attraction in the caput. These caput had little spirals and it worked much like magnetic-tape playback caputs although non in contact with the entering surface. As data denseness increased, read caputs utilizing magneto opposition ( MR ) came into usage. Later development made usage of spintronics. In these caputs, the magneto resistive consequence was much greater that in earlier types, and was dubbed “ elephantine ” magneto opposition ( GMR ) .

Hard disc caput are kept from reaching the platter surface by the air that is highly close to the platter. While the record and playback caput are mounted on a block called a skidder and the surface next to the platter is shaped to maintain it merely hardly out of contact. It is a type of air bearing.

The magnetic surface of each platter is conceptually divided into many little sub-micrometer-sized magnetic parts. Each of which used to encode a individual binary unit of information. In modern thrusts, the little size of the magnetic parts creates the danger that their magnetic province might be lost because of thermic effects. To cover this, the platter are coated with two parallel magnetic beds which separated by a 3-atom-thick bed of the non-magnetic component Ru and the two beds are magnetized in opposite orientation.

Architecture of difficult disc thrust

The stator twists are copper-colored and the motor has an external rotor. The spindle bearing is in the Centre while to the left of Centre is the actuator with a read-write caput under the tip of its very terminal. The orange band along the side of the arm, a thin printed-circuit overseas telegram, connects the read-write caput to the hub of the actuator. The flexible, that ‘U’-shaped, thread overseas telegram hardly seeable below and to the left of the actuator arm is the flexible subdivision. One terminal on the hub that continues the connexion from the caput to the accountant board on the opposite side. The head support arm is really light but besides stiff. While, in the modern thrust, acceleration at the caput reaches 250 gs. The silver-colored construction at the upper left is the top home base of the permanent-magnet and traveling spiral “ motor ” that swings the caputs to the desired place. Beneath this home base is the traveling spiral, attached to the actuator hub, and beneath that is a thin neodymium-iron-boron ( NIB ) high-flux magnet. That magnet is mounted on the bottom home base of the “ motor ” .

The spiral is shaped instead like an arrowhead and it is made of doubly-coated Cu magnet wire. The interior bed is insularity and the outer is thermoplastic, which bonds the spiral together after it ‘s lesion on a signifier and doing it self-supporting. Sing that current flows radically outward along one side of the arrowhead and radically inward on the other. The surface of the magnet is half N pole, half S pole and the dividing line is halfway and extremist.

A difficult disc thrust with the platters and spindle motor hub

Size of the difficult disc thrust

The difficult disc became conversationally named after the corresponding floppy-disk thrusts types. The followers is the different size of the difficult disc thrust:

8 inch

The 1st size of the compatible difficult disc thrust is the Shugart Associates, in 1979

5.25 inch

In 1980, this smaller size of difficult disc thrust is the 1st used in an difficult disc thrust and it was the same size as full tallness 5A? inch diameter floppy disc thrust.

3.5 inch

In 1984, by Rodime, this smaller size was 1st used in a difficult disc thrust.

2.5 inch

Prairie Tek had introduced this smaller size difficult disc thrust in 1988 and there is no corresponding floppy disc thrust.

1.8 inch

This size of difficult disc thrust was originally introduced by Built-in Peripherals in 1993.

1 inch

In 1999, this size of difficult disc was introduced as IBM ; s Microdrive.

0.85 inch

In January 2004, Toshiba had announced this type of difficult disc thrust.

5A? ” full height 110 MB HDD

Six difficult thrusts with 8 ” , 5.25 ” , 3.5 ” ,2.5 ” ,1.8 ” , and 1 ” disc

Floppy Disk

Floppy Disk is another magnetic storage ; it ‘s cased in a square or rectangular plastic shell. This disc merely can be read and written by a floppy disc thrust ( FDD ) . There are many different types of floppy discs, such as 8 inch, 5A?-inch, and the most common or the smaller is 3A?-inch. Into paths, in paths got sector and in the sector is the bytes.

The disc is divided into paths ( brown the paths ) and the sector ( xanthous is the sector ) .

8 Inch Floppy Disk

The first floppy disc was invented is 8 Inch floppy disc by IBM. The first floppy disc was called the “ memory disc ” it keeping 80 Ks and its Single Sided Single Density ( SSSD ) but this floppy disc can read-only. Memorex 650 was the first read-write floppy disc thrust was invented by Memorex in 1972. It had a information capacity of 175kilobytes, with 50 paths, 8 sector per path, and 448 bytes per sector. In 1973, IBM invented a floppy disc thrust, its same with Memorex 650 which it can read-write floppy disc. The different is the capacity ; it can hive away up to 250A? Ks on the same disc. This disc was divided into 77 paths, with 26 sector per path, and 128bytes per sector. In 1976 IBM introduced 500 Ks Double Sided Single Density ( DSSD ) . A twelvemonth after that IBM introduced the 1 to 1.2 Megabytes disc which is Double Sided Double Density ( DSDD ) .

The 8 Inch floppy disc thrust with the floppy disc.

The 8 Inch Floppy disc.

5A? Inch Floppy Disk

In 1976 the 5A? Inch Floppy Disk was invented because of the size of the 8 Inch Floppy Disk is so big for the desktop. The first disc merely cans storage up to 98.5 Kilobytes, subsequently it was increased to 110 Ks. Double-sided thrust was introduced in 1978 it duplicating the capacity and increased the capacity to 360 Ks. At that clip floppy thrust was the primary storage device. The operating system was normally boot from the floppy disc. In the early of 1980 the quad denseness was invented, with 96 paths per inch, it has been increasing the capacity to 720 Ks. In 1984 the high denseness disc appeared. The disc used 96 paths per inch combined with a higher denseness magnetic media to supply 1200 Ks or 1.2 Ms.

The 5A? Inch floppy disc thrust.

The 5A? Inch floppy disc.

3A? Floppy Disk

The 3A? floppy disc is different comparison to old floppy disc it had the stiff instance ‘s slide-in-place metal screen, the advantage by adding the stiff instance ‘s slide-in-place metal screen is to protect the disc surface from the physical contact. The other different is the shell. The 3A? floppy disc shell is harder comparison to the old floppy disc. The single-sided 3A? inch floppy disc capacity is 360 Ks which same with the single-sided 5A? inch floppy disc. In 1986 Apple introduced the double-sided floppy disc which has the 800 Ks capacity, around the same clip the 720 Ks double-sided dual denseness MFM ( Modified Frequency Modulation ) disks began to look on PC-compatibles. In 1987 a newer and better MFM- based was invented which can hive away 1440 Ks or 1.44 Ms. This floppy disc is high-density and displayed as “ HD ” on the underside of the floppy disc. Another floppy disc is extended-density or “ ED ” which can hive away 2880 Ks or 2.88 Ms

The 3A? Inch floppy disc thrust.

The 3A? Inch floppy disc.

Magnetic band card

A magnetic band card, sometimes called magstripe, is a type of card capable of hive awaying informations by modifying the magnetic attraction of bantam iron-based magnetic atoms on a set of magnetic stuff on the card. It is read by physical contact and swiping past a reading caput. They may besides incorporate RFID ticket which is a transponder device or a micro chip largely used for concern premises entree control or electronic payment. Magnetic band cards are normally used in recognition cards, individuality cards, and besides the transit tickets.

The procedure of attaching a magnetic to a fictile card was invented by IBM under a contract with the US authorities for a security system. Forrest Parry, an IBM Engineer, had the thought of procuring a piece of magnetic tape, the prevailing storage medium at the clip, to a fictile card base.

There were a figure of stairss required to change over the magnetic stripy media into an industry acceptable device. These stairss included:

Making the international criterions for band record content, including which information, in what format and utilizing which specifying codifications.

Field proving the proposed device and criterions for market credence.

Developing the fabrication stairss need to mass bring forth the big figure of cards require.

Adding stripe issues and credence capablenesss to available equipment.

The magnetic band is contained in a plastic-like movie. The magnetic band is located 0.233 inches ( 5.66mm ) from the border of the card, and is 0.375 inches ( 9.52mm ) broad. The magnetic band contains three paths, each 0.110 inches ( 2.79mm ) broad. Tracks one and three are typically recorded at 210 spots per inch ( 8.27 spots per millimeter ) , while path two typically has a entering denseness of 75 spots per inch ( 2.95 spots per millimeter ) . Each path can either incorporate 7-bit alphameric characters, or 5-bit numeral characters. Track 1 criterions were created by the air hoses industry ( IATA ) . Track 2 criterions were created by the banking industry ( ABA ) . Track 3 criterions were created by the Thrift-Savings industry. Magstripes following these specifications can typically be read by most point-of-sale hardware, which are merely generic all-purpose computing machines that can be programmed to execute specific undertakings. Examples of cards adhering to these criterions include ATM cards, bank cards ( recognition and debit including VISA and MasterCard ) , gift cards, trueness cards, driver ‘s licences, telephone naming cards, rank cards and about any application in which value or unafraid information is non stored on the card itself.

Smart cards are a newer coevals of card incorporating an integrated circuit bit. The card may hold metal contacts linking the card physically to the reader, while contactless cards use a magnetic field or wireless frequence ( RFID ) for propinquity reading.

Hybrid smart cards include a magnetic band in add-on to the chip-this is most normally found in a payment card, so that the cards are besides compatible with payment terminuss that do non include a smart card reader.

Magnetoresistive Random Access Memory ( MRAM )

Magnetoresistive Random Access Memory ( MRAM ) is a non-volatile computing machine memory engineering that uses electron spin to hive away information. MRAM can replace all the memory in our computing machines. It can defy high radiation, and can run in utmost temperature conditions.


Unlike other RAM bit engineerings, in MRAM informations is non stored as electric charge or current flows, but by magnetic storage elements. The elements are formed from 2 ferromagnetic home bases. One of the two home bases is a lasting magnet set to a peculiar mutual opposition ; the other ‘s field will alter to fit that of an external field. A memory device is built from a grid of such ‘cell ‘ . A peculiar cell is ( typically ) selected by powering an associated transistor which switches current from a supply line through the cell to land. Due to the magnetic tunnel consequence, the electrical opposition of the cell alterations due to the orientation of the Fieldss in the two home bases. Typically if the two home bases have the same mutual opposition this is considered to intend “ 0 ” , while if the two home bases are of opposite mutual opposition the opposition will be higher and this means ” 1 ” .

The toggle manner, uses of a multi-step write with a modified multi-layer cell. The cell is modified to incorporate an “ unreal antiferromagnet ” where the magnetic orientation alternates back and Forth across the surface, with both the pinned and free beds have merely two stable provinces, which can be toggled from one to the other by clocking the write current in the two lines so one is somewhat delayed, thereby “ revolving ” the field. Any electromotive force less than the full write degree increase its opposition to flipping.


MRAM has similar velocities to SRAM, similar denseness of DRAM but much lower power than DRAM, and is much faster and suffers no debasement over clip comparison to blink memory.


There are many types of magnetic storage device. One of them is difficult disc thrust. Difficult disc thrust can be internal or external from the computing machine. In market now, there are a batch of different capacities available. Example, difficult disc with the 80 GB, it ‘s the smallest in the market now. While the capacity of difficult disc thrust up to 1 TB which available in market today. It store informations for good which can hive away until the difficult disc thrust clang. Beside difficult disc thrust, there are besides got other types of magnetic storage device, its floppy disc. Standard floppy discs with the high-density can hive away informations up to 1.44 MB. But the more the other floppy disc with the extended-density can hive away informations up to 2.88 MB. Although the floppy disc is little and thin but the capacity are smaller comparison to other USB flash thrust it has become unpopular right now. Another illustration of magnetic storage device is magnetic stripe card. Magnetic band cards are the most common usage and see in our day-to-day life as we can normally establish magnetic band cards in recognition cards, individuality cards, and besides the transit tickets. MRAM besides is one of the illustrations of magnetic storage device. MRAM is a non-volatile memory that shop information in our computing machine. It besides called as “ the ideal memory ” . One of the advantage of the MRAM is it can defy high radiation, and can run in utmost temperature conditions.

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The Magnetic Storage Devices Computer Science Essay. (2020, Jun 02). Retrieved from

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