Browse Prior Art Database

Skewed Erase Gap for Block Beginning

IP.com Disclosure Number: IPCOM000076154D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Flippen, GB: AUTHOR

Abstract

Defining data blocks on recording tapes with perforations, requires separate sensing means for detecting the perforations for such purposes as addressing and counting.

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Skewed Erase Gap for Block Beginning

Defining data blocks on recording tapes with perforations, requires separate sensing means for detecting the perforations for such purposes as addressing and counting.

A single-channel head having a common read/write gap and a skewed erase gap can be used for defining data blocks. This is accomplished by using the erase gap to write a low-density mark at each desired block beginning location on a tape. The angle of skew will be such that during a normal read/write operation, the mark will be sensed by the erase gap for turning on the read/write control circuitry. Also, the density of the mark is such that during a high-speed search operation, the frequency response of the head will not be exceeded. For either a normal read/write operation or a high-speed search operation, the data contained in the data blocks having a high-recording density will not be detected by the erase gap.

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