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EP0189187A2
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Magnetic-optical disc memory system
Assignee: Hitachi Ltd
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Filing: 1986-01-22
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Granted: —
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Expires: 2006-01-22
Abstract
Abstract @ In a magnetic-optical disc memory system wherein header information items which include sector marks indicating initial positions of sectors, track Nos., and sector Nos. are previously provided on a magnetic-optical disc in the form of embossed pits and wherein data information items are written in the form of magnetic signals in data parts other than the header parts; detection means (8, 11, 13, 14) for the header part and detection means (8, 9, 10, 19) for the data part are disposed, and the operation of switching outputs from both the detection means is controlled in accordance with a timing based on the point of time at which a sector mark signal has been detected from the output of the header part detection means.
Inventors
- 👤 Atsushi Saitoh
- 👤 Toshimitsu Kaku
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 04:34
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B11/00; G11B11/10; G11B11/105; G11B11/10595; G11B11/10597; G11B13/00; G11B13/04; G11B27/102; G11B27/105; G11B20/00; G11B20/10; G11B2020/1087; G11B2020/10888; G11B2220/00; G11B2220/20; G11B2220/25; G11B2220/2525
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
139 words
A magnetic-optical disc memory system wherein header information items including sector marks indicative of initial positions of sectors, track Nos. and sector Nos. are written on a magnetic-optical disc in the form of embossed pits and wherein data information items are writte in the form of magnetic signals in parts other than the header information-written parts on the magnetic-optical disc; characterized in that said system comprises: means (8, 11, 13, 14) to detect the header information; means (8, 9, 10,19) to detect the data information; means (15) to detect the sector mark from an output of the header information detection means; and a switching circuit (20) whose operation of switching pass of the header information and the data information is controlled in accordance with a timing based on a point of time of the detection of the sector mark.
Claim 2
Dependent Claim
139 words
A magnetic-optical disc memory system wherein header information items including sector marks indicative of initial positions of sectors, track Nos. and sector Nos. are written on a magnetic-optical disc in the form of embossed pits and wherein data information items are writte in the form of magnetic signals in parts other than the header information-written parts on the magnetic-optical disc; characterized in that said system comprises: means (8, 11, 13, 14) to detect the header information; means (8, 9, 10,19) to detect the data information; means (15) to detect the sector mark from an output of the header information detection means; and a switching circuit (20) whose operation of switching pass of the header information and the data information is controlled in accordance with a timing based on a point of time of the detection of the sector mark.
Claim 3
Dependent Claim
80 words
A magnetic-optical disc memory system according to claim 1, characterized by further comprising control circuit means (15, 17, 22) to forcibly set said switching circuit (20) in case of access from a certain track being currently tracked to another track, so that only the output of said header information detection means may pass through said switching circuit; the setting of said switching circuit being released on the basis of the detection of the sector mark after end of the access.
Claim 4
Dependent Claim
28 words
A magnetic-optical disc memory system according to claim 2, characterized in that the detection of the sector mark is performed at a stage posterior to said switching circuit.
Claim 5
Dependent Claim
82 words
A magnetic-optical disc memory system according to claim 2, characterized in that said control circuit means (22) comprises a delay circuit (30) which delays a sector mark signal; a flip-flop circuit (33) which is controlled by an output of said delay circuit (30) and an access instruction signal (23); and an AND circuit (35) which is supplied with an output (34) of said flip-flop circuit (33) and a gate signal (218) for controlling the switching operation of said switching circuit. (Fig. 7)
References Cited (Backward Citations)
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