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Stabilization Of Multisurface Files

IP.com Disclosure Number: IPCOM000049415D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Moore, JA: AUTHOR [+2]

Abstract

Many early life failures of disk files are due to an excessive mechanical shift of parts within the disk enclosure. Some movement of these parts is anticipated, such as expansion and contraction due to temperature change, and is provided for in the initial design.

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This is the abbreviated version, containing approximately 90% of the total text.

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Stabilization Of Multisurface Files

Many early life failures of disk files are due to an excessive mechanical shift of parts within the disk enclosure. Some movement of these parts is anticipated, such as expansion and contraction due to temperature change, and is provided for in the initial design.

This movement is particularly a problem in multidisk, multiheaded files. The problem is further enhanced by a servo scheme wherein a burst of servo data is written on each track of each head and this data is used to "track follow" whenever that head is selected.

Investigation of the failed devices has shown that the movement that had occurred was much larger than had been expected. Also, it was discovered that because of the movement, the head to servo head relationship stayed in its new position, and had not returned to its original condition as would occur with normal expansion/contraction movement. This excessive shift was found to be caused by stresses built into the file which. over time and temperature, tend to relieve themselves. Virtually every screw, bolt, and part can contribute to the total stress induced.

It was found that a large part of the built-in stress could be removed by subjecting the disk enclosure to hot and cold temperature extremes for a period of time prior to writing the servo pattern on the disk surface. The temperatures used were -40 degrees F and +140 degrees F. The units were subjected to each temperature extreme for 8 hours. The unit was...