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Eccentricity Tolerant Head Alignment Check

IP.com Disclosure Number: IPCOM000083265D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Sibbers, DE: AUTHOR

Abstract

The testing of the alignment of a disk drive sensing head must also allow for several other factors that influence head alignment. The principal other factors are temperature, humidity and eccentric alignment of the disk and spindle. These conditions are aggravated in the case of flexible disks and flexible-disk drives in that there is a greater tendency to encode on one device and read on another, and to store and use the disk media in more widely varying temperature and humidity conditions. Temperature and humidity corrections can be largely overcome, by allowing a testing device to assume the environmental conditions at the machine location.

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Eccentricity Tolerant Head Alignment Check

The testing of the alignment of a disk drive sensing head must also allow for several other factors that influence head alignment. The principal other factors are temperature, humidity and eccentric alignment of the disk and spindle. These conditions are aggravated in the case of flexible disks and flexible-disk drives in that there is a greater tendency to encode on one device and read on another, and to store and use the disk media in more widely varying temperature and humidity conditions. Temperature and humidity corrections can be largely overcome, by allowing a testing device to assume the environmental conditions at the machine location.

As shown schematically in Fig. 1, a disk is arranged with 26 records in each track as illustrated by the radial segments. Each record includes a short identifier field 5 and a longer data field 6, represented by the radially offset arcuate lines within each segment. The radial offset between the two elements of each record is representative of the allowable tolerance.

As shown in Fig. 2, two circles are illustrative of a recorded track 3 or the sweep of the head during writing, and the as read track 4 or the sweep of the head during reading. The double-headed arrows 7 and 8 are representative of track length record portions where minimum error occurs, as a result of eccentricity between centers of rotation 3' and 4'. If the drive is capable of reading a pair of records disposed 18...