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Browse Prior Art Database

Flexible File Head Alignment

IP.com Disclosure Number: IPCOM000050703D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Goodwin, JG: AUTHOR

Abstract

The procedure is to set up a "go-no go" system by which flexible file head alignment can be performed. The problem with using only one diskette to check alignment is that humidity will cause diskettes to grow. When the diskettes grow, the alignment tracks will no longer be in the same position as when the diskettes were written.

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Flexible File Head Alignment

The procedure is to set up a "go-no go" system by which flexible file head alignment can be performed. The problem with using only one diskette to check alignment is that humidity will cause diskettes to grow. When the diskettes grow, the alignment tracks will no longer be in the same position as when the diskettes were written.

The method of a go-no go test can be performed by using three diskettes with special data pattern that are written at the same time. The three diskettes are used in conjunction with a reference drive and two oscilloscopes. The reference drive has its head set in the nominal head position for a standard track dimension. One of the diskettes has special data written on track. This diskette is for reference drive uses only. The reference drive is used to show the amount of change the diskette experiences due to humidity.

The other two diskettes have special data written off track by the amount of the electrical tolerance. One diskette will check for an over high-limit condition, and the other diskette will check for an under low-limit condition. The special pattern that is written on the diskettes in designed to show a shift of .001 inch between head and media.

With the head set at nominal, the center lines of the scope trace alignment pattern are even, as shown in Fig. 1. The alignment patterns of Figs. 1, 2 and 3 were generated with the standard alignment diskette (the first special diskette). Each line that is crossed starting horizontally from the lower amplitude center line indicates an 0.2 mil deviation.

Fig. 2 illustrates a head set 0.4 mil above nominal (away from the hub). Two lines are crossed by the horizontal dotted one extending from the end of the minus center line representing an 0.4 mil deviation. If the nominal setting for the head is 0.02 inch, this drive would actually be set at 0.0196 inch. For a head positioned 0.6 mil below nominal (toward the hub), the alignment pattern would be as shown in Fig....