346:
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 0.5 micrometers in size) in a plastic binder on polyester film tape. 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 1990s, however, tape recording has declined in popularity due to digital recording.
117:
435:, 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. In the case of magnetic wire, the read/write head only covers a very small part of the recording surface at any given time. 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.
31:
212:
414:. 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. Data is then recorded by the presence/absence of a bubble domain. Domain propagation memory has high insensitivity to shock and vibration, so its application is usually in space and aeronautics.
345:
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
438:
Hard disks and modern linear serpentine tape drives do not precisely fit into either category. Both have many parallel tracks across the width of the media and the read/write heads take time to switch between tracks and to scan within tracks. Different spots on the storage media take different
324:
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
573:
rather than using standard electropulses for writing data on magnetic storage media. By using terahertz radiation, writing time can be reduced considerably (50x faster than when using standard electropulses). Another advantage is that terahertz radiation generates almost no heat, thus reducing
223:
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.
285:
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
558:
cannot support due to its limited write endurance. Six state MRAM is also being developed, echoing four bit multi level flash memory cells, that have six different bits, as opposed to
290:
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.
967:
490:
see some marginal usage, particularly in dealing with older computer systems and software. Magnetic storage is also widely used in some specific applications, such as bank
390:, 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
144:. Smith had previously filed a patent in September, 1878 but found no opportunity to pursue the idea as his business was machine tools. The first publicly demonstrated
1016:
394:. 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
317:(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
309:(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
447:
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
293:
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
843:
478:. 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.
474:
As of 2021, 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
857:
522:(TMR) effect. Its advantage is non-volatility, low power usage, and good shock robustness. The 1st generation that was developed was produced by
259:(HDD) designs the regions were oriented horizontally and parallel to the disk surface, but beginning about 2005, the orientation was changed to
973:
116:
1109:
603:
511:
1009:
96:
is more commonly used. The distinction is less technical and more a matter of preference. Other examples of magnetic storage media include
812:
463:
1073:
960:
700:
624:
612:
1147:
1002:
618:
153:
1152:
554:, MRAM is useful in applications where moderate amounts of storage with a need for very frequent updates are required, which
550:, and several other companies are working. However, with storage density and capacity orders of magnitude smaller than an
439:
amounts of time to access. For a hard disk this time is typically less than 10 ms, but tapes might take as much as 100 s.
145:
1137:
678:
630:
566:
793:
527:
479:
946:
1157:
298:
746:
E. du Trémolete de
Lacheisserie, D. Gignoux, and M. Schlenker (editors), Magnetism: Fundamentals, Springer, 2005
374:. HDDs offer large capacities at reasonable prices; as of 2024, consumer-grade HDDs offer data storage at about
519:
428:
220:
66:
988:"Know Your Digital Storage Media: a guide to the most common types of digital storage media found in archives"
523:
318:
314:
260:
35:
865:
386:
Magneto-optical recording writes/reads optically. When writing, the magnetic medium is heated locally by a
1142:
641:(1916–1995), American electrical engineer and inventor, major contributor to magnetic recording technology
953:
659:
239:
nature of the magnetic material, each of these magnetic regions is composed of a few hundred magnetic
1067:
1055:
588:
535:
499:
432:
105:
526:, and utilized field induced writing. The 2nd generation is being developed through two approaches:
313:; in read heads, the magnetoresistive effect was much greater than in earlier types, and was dubbed
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62:
30:
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459:
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in a rigorous physical sense), each of which has a mostly uniform magnetisation. Due to the
232:
192:
188:
149:
77:
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Information is written to and read from the storage medium as it moves past devices called
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367:
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176:
73:
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1037:
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audio signals. Computers and now most audio and video magnetic storage devices record
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1103:
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598:
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475:
411:
294:
200:
180:
165:
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137:
125:
101:
58:
203:. Unlike modern computers, magnetic tape was also often used for secondary storage.
593:
555:
483:
169:
701:"IBM OEM MR Head | Technology | The era of giant magnetoresistive heads"
231:-sized magnetic regions, referred to as magnetic domains, (although these are not
215:
Hard drives use magnetic memory to store giga- and terabytes of data in computers.
1097:
1049:
487:
391:
363:
326:
310:
240:
236:
184:
97:
243:. Magnetic grains are typically 10 nm in size and each form a single true
371:
359:
228:
124:(from 1979) could store data via an external magnetic tape storage device on
17:
983:
VOLUME 43 NUMBER 7 JULY 2006 "Magnetic
Recording a Revolutionary Technology"
551:
448:
302:
940:
797:
301:. Later versions of inductive heads included Metal In Gap (MIG) heads and
297:
both to magnetise the region and to then read its magnetic field by using
1085:
994:
395:
486:
are popular for the high capacity data storage of archives and backups.
358:
only needs two stable magnetic states, which are the +Ms and −Ms on the
491:
910:
354:
Instead of creating a magnetisation distribution in analog recording,
92:
is preferred and in the field of audio and video production, the term
987:
279:
121:
54:
543:
387:
210:
115:
85:
81:
29:
227:
The magnetic surface is conceptually divided into many small sub-
515:
495:
399:
50:
998:
547:
955:
Oberlin Smith and the
Invention of Magnetic Sound Recording
756:
627:(PMR), also known as conventional magnetic recording (CMR)
321:
while the write element is typically thin-film inductive.
61:
in a magnetizable material to store data and is a form of
164:. Early magnetic storage devices were designed to record
911:"Prof. Kimel, A.V. (Aleksei) | Radboud University"
57:
medium. Magnetic storage uses different patterns of
569:
278:) as the magnetic material, but current disks use a
427:Magnetic storage media can be classified as either
305:heads. As data density increased, read heads using
858:"Tower invests in Crocus, tips MRAM foundry deal"
175:In computers, magnetic storage was also used for
65:. The information is accessed using one or more
703:. Hitachigst.com. 27 August 2001. Archived from
565:Research is also being done by Aleksei Kimel at
458:Many magnetic disks internally use some form of
887:"Researchers design six-state magnetic memory"
1010:
768:Prices are lower for used/refurbished drives.
263:to allow for closer magnetic domain spacing.
136:—audio recording on a wire—was publicized by
88:signals. In the field of computing, the term
8:
530:(TAS) which is currently being developed by
38:, two types of writing heads on a hard disk
1017:
1003:
995:
990:. USA: University of Texas at San Antonio.
156:on a wire wrapped around a drum. In 1928,
27:Recording of data on a magnetizable medium
679:"A divide over the future of hard drives"
410:Domain propagation memory is also called
247:. Each magnetic region in total forms a
650:
514:or MRAM, is being produced that stores
510:A new type of magnetic storage, called
948:Selected History of Magnetic Recording
842:: CS1 maint: archived copy as title (
835:
604:Magnetoresistive random-access memory
512:magnetoresistive random-access memory
152:in 1898. Poulsen's device recorded a
7:
963:on the UC San Diego web site (CMRR).
677:Kanellos, Michael (24 August 2006).
451:. Most magnetic storage devices use
362:. Examples of digital recording are
120:The programmable calculators of the
464:partial-response maximum-likelihood
148:magnetic recorder was invented by
72:Magnetic storage media, primarily
25:
810:The Emergence of Practical MRAM
625:Perpendicular magnetic recording
613:Heat-assisted magnetic recording
132:Magnetic storage in the form of
780:Complete Electronic Media Guide
729:. Hyperphysics.phy-astr.gsu.edu
619:Longitudinal magnetic recording
518:in magnetic bits based on the
325:contact. This forms a type of
1:
961:History of Magnetic Recording
941:History of Magnetic Recording
759:. Legitimate Data Company LLC
160:developed the first magnetic
140:in the Sept 8, 1888 issue of
794:"MRAM Technology Attributes"
609:Magnetic recording methods:
266:Older hard disk drives used
631:Shingled magnetic recording
76:, are widely used to store
34:Longitudinal recording and
1174:
658:Ley, Willy (August 1965).
528:thermal-assisted switching
498:) and credit/debit cards (
333:Magnetic recording classes
146:(Paris Exposition of 1900)
1033:
727:"Magnetic Tape Recording"
406:Domain propagation memory
382:Magneto-optical recording
315:"giant" magnetoresistance
299:electromagnetic induction
662:. For Your Information.
520:tunnel magnetoresistance
429:sequential access memory
927:Kijk magazine, 12, 2019
36:perpendicular recording
1148:Computer storage media
970:of Magnetic Recording.
664:Galaxy Science Fiction
574:cooling requirements.
216:
129:
39:
1153:Magnetic data storage
660:"The Galactic Giants"
524:Everspin Technologies
214:
119:
33:
975:" Science Reporter,
589:Digital Data Storage
536:spin-transfer torque
433:random access memory
221:read-and-write heads
1138:American inventions
666:. pp. 130–142.
571:terahertz radiation
63:non-volatile memory
757:"Disk Prices (US)"
584:Digital Audio Tape
567:Radboud University
460:run-length limited
251:which generates a
217:
130:
94:magnetic recording
49:is the storage of
47:magnetic recording
40:
1125:
1124:
800:on June 10, 2009.
532:Crocus Technology
418:Technical details
356:digital recording
350:Digital recording
319:magneto-resistive
307:magnetoresistance
108:on credit cards.
16:(Redirected from
1165:
1158:Magnetic devices
1026:Magnetic storage
1019:
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1005:
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928:
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864:. Archived from
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848:
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824:
818:. Archived from
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796:. Archived from
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453:error correction
377:
368:hard disk drives
343:Analog recording
338:Analog recording
233:magnetic domains
193:thin film memory
189:core rope memory
150:Valdemar Poulsen
142:Electrical World
106:magnetic stripes
90:magnetic storage
67:read/write heads
43:Magnetic storage
21:
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813:"Archived copy"
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538:(STT) on which
508:
472:
445:
425:
420:
408:
384:
376:US$ 15–20
375:
360:hysteresis loop
352:
340:
335:
288:magnetic moment
277:
273:
268:iron(III) oxide
257:hard disk drive
249:magnetic dipole
245:magnetic domain
237:polycrystalline
209:
177:primary storage
114:
28:
23:
22:
15:
12:
11:
5:
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934:External links
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783:. 2004. p. 22.
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681:. CNETNews.com
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484:tape libraries
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443:Coding schemes
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404:
383:
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378:per terabyte.
351:
348:
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336:
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331:
282:-based alloy.
275:
271:
253:magnetic field
208:
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197:twistor memory
158:Fritz Pfleumer
134:wire recording
126:microcassettes
113:
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26:
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10:
9:
6:
4:
3:
2:
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1143:Storage media
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868:on 2012-01-19
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839:
825:on 2011-04-27
821:
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777:Allen Lloyd.
774:
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719:
707:on 2015-01-05
706:
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639:Marvin Camras
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599:Karlqvist gap
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470:Current usage
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423:Access method
422:
417:
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412:bubble memory
405:
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398:developed by
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261:perpendicular
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206:
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201:bubble memory
198:
194:
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186:
182:
181:magnetic drum
179:in a form of
178:
173:
171:
167:
163:
162:tape recorder
159:
155:
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147:
143:
139:
138:Oberlin Smith
135:
127:
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103:
102:magnetic tape
99:
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79:
78:computer data
75:
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68:
64:
60:
59:magnetisation
56:
52:
48:
44:
37:
32:
19:
18:Magnetic disk
1056:Ferrite core
1025:
954:
947:
923:
914:
905:
894:. Retrieved
890:
881:
870:. Retrieved
866:the original
861:
852:
827:. Retrieved
820:the original
806:
798:the original
788:
779:
773:
761:. Retrieved
751:
742:
731:. Retrieved
721:
709:. Retrieved
705:the original
695:
683:. Retrieved
672:
663:
653:
594:Disk storage
564:
556:flash memory
509:
488:Floppy disks
480:Digital tape
473:
457:
446:
437:
426:
409:
385:
370:(HDDs), and
364:floppy disks
353:
341:
323:
292:
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226:
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174:
170:digital data
141:
131:
122:HP-41-series
98:floppy disks
93:
89:
71:
46:
42:
41:
1098:Floppy disk
1068:Stripe card
711:4 September
500:mag stripes
476:analog tape
462:coding and
392:Kerr effect
372:tape drives
327:air bearing
311:spintronics
255:. In older
185:core memory
80:as well as
1132:Categories
968:Chronology
943:(BBC/H2G2)
896:2016-05-23
872:2014-01-28
829:2009-07-20
763:2024-03-10
733:2014-01-28
646:References
229:micrometer
74:hard disks
55:magnetized
1116:Racetrack
1080:Thin film
1062:Hard disk
981:0036-8512
915:www.ru.nl
449:DC offset
303:thin film
891:phys.org
862:EE Times
838:cite web
578:See also
396:Minidisc
1106:(~1970)
1094:(~1968)
1092:Twistor
685:24 June
492:cheques
112:History
1118:(2008)
1112:(1995)
1104:Bubble
1100:(1969)
1088:(1962)
1082:(1962)
1076:(1956)
1070:(1956)
1064:(1956)
1058:(1949)
1052:(1932)
1046:(1928)
1040:(1898)
979:
615:(HAMR)
606:(MRAM)
540:Crocus
534:, and
506:Future
280:cobalt
241:grains
207:Design
166:analog
154:signal
104:, and
1028:media
823:(PDF)
816:(PDF)
633:(SMR)
621:(LMR)
544:Hynix
388:laser
183:, or
86:video
82:audio
53:on a
1110:MRAM
1086:CRAM
1074:MICR
1050:Drum
1044:Tape
1038:Wire
977:ISSN
844:link
713:2010
687:2010
516:data
496:MICR
482:and
400:Sony
84:and
51:data
560:two
552:HDD
548:IBM
502:).
431:or
270:(Fe
199:or
45:or
1134::
966:A
939:A
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889:.
860:.
840:}}
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