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Browse Prior Art Database

Actuator Positioning for Selection of Disks

IP.com Disclosure Number: IPCOM000087153D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Lieber, R: AUTHOR [+3]

Abstract

A pack of spaced flexible storage disks clamped coaxially between end plates which are not axially shiftable is internally actuated (see pages 2640-2641 of this issue) to a state of peripheral separation suitable for recording and reproduction access to any desired storage surface. The pack and end plates rotate as a unit at a predetermined recording speed. The pack may contain from several hundred to several thousand disks. It is desirable, for volumetric efficiency and other reasons, to be able to control the internal actuator without the use of sensory apparatus to monitor or count the edges of the storage disks and interstitial spaces.

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Actuator Positioning for Selection of Disks

A pack of spaced flexible storage disks clamped coaxially between end plates which are not axially shiftable is internally actuated (see pages 2640-2641 of this issue) to a state of peripheral separation suitable for recording and reproduction access to any desired storage surface. The pack and end plates rotate as a unit at a predetermined recording speed. The pack may contain from several hundred to several thousand disks. It is desirable, for volumetric efficiency and other reasons, to be able to control the internal actuator without the use of sensory apparatus to monitor or count the edges of the storage disks and interstitial spaces.

The present method accomplishes this. The disks and end plates are packaged as a cartridge unit. Alternate recording disks are separated by thin, small diameter metal spacer disks which have radial grooves permitting stabilizing centrifugal air circulation through the bore space formed by aligned apertures in all disks (preferably the space in which the internal actuator will operate). At the assembly site (e.g., the factory), the unit is mounted without rotation upon calibration apparatus containing a slidably displaceable sensor which is insertable in the bore space. The apparatus is fitted (e.g., with a head inductively coupled to the spacer material) for accurately determining the thickness mid-plane location of each spacer disk and for producing digital representations which correspond to the displacement distances of successive spacer disk mid-planes relative to a reference plane (e.g., a surface of one of the end plates).

A predetermined number of storage disks near each end plate are not sufficiently displaceable for access and are not used. The number (minimum) of such disks is empirically determinable and constant for all packs of a given design. The distances to the mid-planes of the interstitial spaces communicating with the useful recording surfaces are thereby determinable by simple calculation. Thus, the calibrat...