Boots – shoes – and leggings
Patent
1981-03-26
1984-04-24
Chin, Gary
Boots, shoes, and leggings
360 75, 360106, G11B 2102, G11B 555
Patent
active
044451881
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method and apparatus whereby the attritional wear, encountered between the reading and writing transducer and the rotating media of certain styles of disc files, is distributed accross the entire data storage surface of the media, thereby eliminating the local nature of the attritional wear, and extending the working life expectancy of the media.
In particular, the present invention relates to an apparatus for the storage of retrievable, informational data on rotating media, where the media is subject to attritional wear as a result of the mechanical interaction between the surface of the media and a radially mobile transducer, wherein there is provided an apparatus, keeping the transducer radially mobile accross the surface of the rotating media at all times that the transducer is not required, by the normal operation of the disc file, to stay still, the apparatus so distributing the attritional wear accross the entire media data storage surface, and thereby preventing the early end of life of the media resultant from localised attrition destroying the data storage properties of the media in one location before significant wear has occurred at others.
More particularly, the present invention relates to a disc file for use with flexible, magnetic discs, retrievable, informational data being stored in a plurality of concentric, data storage tracks on the rotating disc, wherein the disc is accessed by the contacting of a radially mobile reading and writing head with the disc surface, there being provided an apparatus whereby the head is kept constantly mobile accross the disc surface at all times that the head is not required, by the normal operations of the disc file, to stay still, so eliminating local attrition of the disc magnetic coating by the head remaining too long at any particular radius on the disc, and eliminating too long at any particular radius on the disc, and eliminating the subsequent loss of individual data tracks before other data tracks have encountered significant wear.
THE PRIOR ART
In the early style of disc files, a magnetic, data storage, disc file universally employed rigid, rotating media, over which a reading/writing magnetic head was flown, at a height of a few hundreds of microinches, on a film of air, which was dragged round by the rapidly rotating, smooth disc. The smoothness of the disc was such that the bumps on the disc never exceeded the flying height of the head, and so the head never touched the disc surface. There was thus little or no frictional wear between the head and the disc, since the only time that contact existed between the two was during a failure condition, when the head was not flying or the disc not rotating.
The introduction of the low cost, easily stored, and small sized, flexible disc, brought with it various head and disc problems. Firstly, the disc was mechanically small, weak, and could not readily be caused to rotate at the high angular speeds necessary for the head to fly on a film of air, dragged round by the disc. Secondly, the smooth disc surfaces possible on the earlier rigid discs, which were fabricated from plated metal, were not possible to achieve in the manufacture of flexible discs, fabricated from buffed and cut polymer sheet. What flying height could be achieved by the heads, was not sufficient to allow the head to clear the bumps or the flexure distortions on the flexible disc. Thirdly, the continuing trend toward higher data densities on all styles of disc necessitated, for considerations given later, that the distance between the head and the surface of the disc be made extremely small indeed.
The flexible disc, popularly known as the "floppy" disc, consists of a circular lamina, cut from a polymer sheet, such as mylar, a few thousandths of an inch thick, and coated on one or both surfaces with a uniform layer, generally less than a hundred microinches thick, of magnetic material, usually composed of finely divided oxides of iron, held together by a passive, binder substance.
In use, the disc is
REFERENCES:
patent: 3609721 (1971-09-01), Meneley
patent: 3632900 (1972-01-01), Kurzwell, Jr.
patent: 3860958 (1975-01-01), Hanson
patent: 4146911 (1979-03-01), Gyi et al.
patent: 4237501 (1980-12-01), Barmache et al.
"Integrated Burnish and Glide Head Instrumentation for Disk Process", published in IBM Tech. Disclosure Bulletin, vol. 21, No. 9, Feb. 1979, pp. 3761-3762.
"Multiple Band Loading Zone for Direct-Access Storage Devices", published in IBM Tech. Disclosure Bulletin, vol. 21, No. 11, Apr. 1979, p. 4648.
"Breakthrough in Random Access Technology" by Fardell, Published in Electronics Weekly, No. 637, Nov. 12, 1972.
Burroughs Corporation
Chin Gary
Chung Edmund M.
Peterson Kevin R.
Rasmussen David G.
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