Fujitsu Corporation

Ken-ichi Itoh

Miyozo Maeda

Kenichi Utsumi

Nagaaki Koshino

Akira Ushioda

Yasuyuki Goto

Itaru Shibata

Kozo Sueishi

Seiya Ogawa

Yasunobu Hashimoto

Yuji Inouye

Shigeru Fukushima

Yutaka Nakamura

Jun Takahashi

Takahiro Imamura

Shintaro Sato

Arata Ejiri

Tsugio Kumai

Toshikatu Narumi

A head is moved in a lateral direction on the boundary between a separation track and a recording track on a recording medium. The separation track isolates the adjacent recording tracks from each other. A variation is detected in the output supplied from the head based on the recording track. Positional information indicating the position of the head is generated based on the variation. The output supplied from the head varies in response to the movement in the lateral direction, namely the elapsed time. The positional information can thus be generated based on the variation in the output. The generated positional information contributes to an accurate positioning in a facilitated manner. Moreover, information required to position the head can be omitted from the recording medium. The processes can be simplified in the production of the recording medium. The operation time can thus be shortened.

Method of detecting position of head for recording medium

A magnetic recording medium is disclosed that includes a substrate; an anodic alumina film formed on the substrate; a pore formed in the anodic alumina film; a carbon layer covering the surface of the anodic alumina film and the inner wall of the pore; a magnetic particle formed on the carbon layer inside the pore; and a lubrication layer covering the carbon layer and the magnetic particle.

Magnetic recording medium, method of manufacturing the same, magnetic medium substrate employed in the magnetic recording medium, and magnetic storage unit

A method for overwriting information in a magneto-optical memory medium which includes a simultaneous writing and erasing step of continuously irradiating a written information-carrying area of the recording layer of the memory medium with two different pulses from a single laser beam head in accordance with information to be written, regardless of the presence or absence of written information. A variation includes irradiating the written information-carrying area with an erasing pulse from a laser beam head, regardless of the presence or absence of written information, and then selectively irradiating the information-erased area with a writing pulse from another laser beam head in accordance with information to be written. According to these methods, it becomes possible to carry out a simple and high-speed overwriting with an increased and stabilized bit positioning accuracy.

Magneto optical overwriting methods using a single optical head designed

A method of overwriting information in a magneto-optical memory medium which includes a simultaneous writing and erasing step of continuously irradiating a written information-carrying area of the recording layer of the memory medium with two different pulses from a single laser beam head in accordance with information to be written, regardless of the presence or absence of written information. A variation includes irradiating the written information-carrying area with an erasing pulse from a laser beam head, regardless of the presence or absence of written information, and the then selectively irradiating the information-erased area with a writing pulse from another laser beam head in accordance with information to be written. According to these methods, it becomes possible to carry out a simple and high-speed overwriting with an increased and stabilized bit positioning accuracy.

Magneto-optical overwriting methods using erasing pulses, each of which

Recording and erasing optical information can be done by using an alloy film capable of forming two stable crystalline states differing in crystal texture and optical characteristics by being irradiated with optical energies under different conditions. A thin memory film preferably including 60 to 90 atom % of Indium (IN) and 10 to 40 atom % of Bismuth (Bi) is formed on a substrate.

Optical information memory medium including indium (In) and bismuth (Bi)

Recording and erasing optical information can be done by using an alloy film capable of forming two stable crystalline states differing in crystal texture and optical characteristics by being irradiated with optical energies under different conditions. The thin memory film preferably includes not more than 60 atom % of Gallium (Ga) and not less than 40 atom % of Antimony (Sb).

Optical information memory medium recording and erasing information

Recording and erasing optical information can be done by using an alloy film capable of forming two stable crystalline states differing in crystal texture and optical characteristics by being irradiated with optical energies under different conditions. The memory film includes 35-45 atom % of indium (In) and 55-65 atom % of antimony (Sb). The memory film may include an additional element M selected from the group consisting of Al, Si, P, S, Zn, Ga, Ge, As, Se, Ag, Cd, Sn, Te, Tl, Pb, Bi, and a combination of these elements, the composition of the memory film being expressed by the formula (In.sub.x Sb.sub.1-x).sub.1-y M.sub.y.

Method for recording information in an optical information memory medium

Recording and erasing optical information can be done by using an alloy film capable of forming two stable crystalline states differing in crystal texture and optical characteristics by being irradiated with optical energies under different conditions. The memory film includes 35-45 atom % of Indium (In) and 55-65 atom % of antimony (Sb).

Optical information memory medium for recording and erasing information

A longitudinal magnetic coated recording medium comprises at least plane magnetic particles each having an easy magnetization axis perpendicular to the major surface thereof, preferably mixed with other particles, and dispersed in a magnetic film formed on a nonmagnetic substrate, having a orientation angle of -30.degree. to +30.degree.. A process for producing such a recording medium comprises the step of orienting the plane magnetic particles by applying at least a magnetic field approximately in parallel to the surface of the magnetic film.

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Yamato, Japan

Ken-ichi Itoh