Browse Prior Art Database

Single Gap Head for Recording and Tunnel Erasing

IP.com Disclosure Number: IPCOM000085100D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Bowen, AJ: AUTHOR

Abstract

Transducer 11 having a single gap 18 is effective for providing a tunnel erase action with respect to rotatable magnetic disk 12, by first applying a relatively high DC "erase" current to the winding 17 of transducer 11 on a first revolution of disk 12, and for subsequently writing data on disk 12 by conventional means on a second revolution of disk 12.

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Single Gap Head for Recording and Tunnel Erasing

Transducer 11 having a single gap 18 is effective for providing a tunnel erase action with respect to rotatable magnetic disk 12, by first applying a relatively high DC "erase" current to the winding 17 of transducer 11 on a first revolution of disk 12, and for subsequently writing data on disk 12 by conventional means on a second revolution of disk 12.

In operation, the first revolution of disk 12 is utilized for erasing a track by simply applying a DC erase current to coil 17. Assuming a physical width of gap 18 (extending radially of disk 12) of 10 milliinches, disk 12 may be erased beyond the 10 milliinch physical width of gap 18 by 800 microinches on each end of gap 18, using a disk saturating DC current of three times the normal write current.

At higher currents (5 times), the total increase on each end of gap 18 may be
1.3 milliinches. Thus, the erase width can be varied to suit the requirements dictated by an application's tracking tolerances. On the second revolution of disk 12, the data is written by conventional means, and the winding current may be held to values limiting writing by transducer 11 to no more than its physical width.

Thus, using the single-gap transducer 11 as described provides a tunnel erasing action which overcomes many track registration problems, and obviates the use of dual gaps or any requirement to offset a single-gap head 11 radially of the disk 12 for tunnel erasing. This method...