Browse Prior Art Database

Reading Phase Encoded Data

IP.com Disclosure Number: IPCOM000091968D
Original Publication Date: 1968-Jul-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Yakkel, GL: AUTHOR

Abstract

The initial synchronization burst is checked as it is written on a magnetic recording medium, such as magnetic tape, to ensure that it is of sufficient length for synchronization during a read operation. Sensing of the beginning of the synchronization burst of a record primes a logical timeout to sample the recording results and to provide an error indication if all tracks are not properly present.

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Reading Phase Encoded Data

The initial synchronization burst is checked as it is written on a magnetic recording medium, such as magnetic tape, to ensure that it is of sufficient length for synchronization during a read operation. Sensing of the beginning of the synchronization burst of a record primes a logical timeout to sample the recording results and to provide an error indication if all tracks are not properly present.

The format for phase-encoded data on magnetic tape 10 includes an interrecord gap IRG which is devoid of all magnetic recording. For reading synchronization, the IRG is followed by a 0's burst zone and an all 1's byte 11. Write check circuits operate to determine that all tracks are present before data is recorded, but do not determine whether these tracks are all present for a sufficient length of time to ensure reading circuitry synchronization before reaching the data zone. For instance, the defect shown as dashed line 12, which could be caused by a tape crease or scratch, can extend so that the width of the 0's burst between the end of the defect at 14 and 11 is not of sufficient length to permit proper reading synchronization.

A signal appearing at terminal 15 indicates initiation of a write operation. The signal at terminal 16 indicates that at least one track has data recorded on it. Thus, for the example shown, a signal appears at 16 when the presence of a signal is detected for one or more of the lower tracks at the beginning of the 0's burst even though 12 prevents all tracks f...