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Sector Servo for Record Storage Apparatus

IP.com Disclosure Number: IPCOM000088187D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Aziz, RA: AUTHOR

Abstract

In certain magnetic or optical storage apparatus it is desirable to use a dual-gap head including the read/write gap R/W and a preceding erase gap E. It is desired to reduce the cost of the two-gap head by placing the gaps as far apart as possible. It is also desired to use sector servoing, i.e., servo data interleaved with data signal areas. In order to avoid interaction between the data signals and the servo signals, as well as avoiding inadvertent destruction of the servo signals by data signal recording, interblock gaps (IBGs) are disposed between the servo and the signal data areas. Such IBGs utilize valuable recording space on either disk or tape.

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Sector Servo for Record Storage Apparatus

In certain magnetic or optical storage apparatus it is desirable to use a dual-gap head including the read/write gap R/W and a preceding erase gap E. It is desired to reduce the cost of the two-gap head by placing the gaps as far apart as possible. It is also desired to use sector servoing, i.e., servo data interleaved with data signal areas. In order to avoid interaction between the data signals and the servo signals, as well as avoiding inadvertent destruction of the servo signals by data signal recording, interblock gaps (IBGs) are disposed between the servo and the signal data areas. Such IBGs utilize valuable recording space on either disk or tape.

In order to reduce the size of the IBG, the intergap spacing between the gaps E and R/W are designed to be slightly greater than the circumferential or longitudinal extent of the servo signals, i.e., the gaps bracket the servo signals, as seen in the drawing.

The procedure for operating with such a format arrangement is that on a first pass of the data signal area to be recorded, erase gap E senses the servo signal for accurately positioning the head for AC erasing the data signal area. On the second pass, read/write gap R/W senses the servo signals and then records new signals into the data area. Of course, during a read operation the erase gap is not energized and only a single pass is required.

The servo channel can respond to a detected envelope signal received from the E gap a...