Browse Prior Art Database

Fast Access Disk Store

IP.com Disclosure Number: IPCOM000093608D
Original Publication Date: 1967-Nov-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 61K

Publishing Venue

IBM

Related People

Anacker, W: AUTHOR

Abstract

In this access disk store, the average access time as well as the maximum access time to any track is comparable to the access times found in drum stores. This is realized without diminishing the full storage capacity of the disk store.

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Fast Access Disk Store

In this access disk store, the average access time as well as the maximum access time to any track is comparable to the access times found in drum stores. This is realized without diminishing the full storage capacity of the disk store.

Such reduction of the access time is achieved by arranging the data tracks 2, 2', 2'', 2''', etc., spirally rather than circularly on the disk surfaces. As shown in drawing 1 where four tracks are used to demonstrate the principle of operation, each track originates on the same circle 4 and has a length approximately equal to the circumference of the disk. Since each track originates from the same circle, each track can be reached during a single revolution of the disk by a single read-write head. The latter is positioned above the circle and without head movement prior to the read or write operation.

Drawing 2 shows a different track arrangement. The track network is more complex and provides for a 512 track disk surface that is subdivided into 16 bands of 32 spiral tracks each. Thus each circle originates 32 tracks.

When spiral tracks are employed, a mechanism for moving a read-write head assembly continuously, without vibration and precisely in a radial direction with respect to the storage surface during read and write operations is provided. The top view drawing 3A and side view drawing 3B show a bar 6 carrying several fixed read-write heads 8. Bar 6 is held in an outward position away from the center of the storage disk by spring 10 whose tension is in the direction of the arrow. Eight independently controllable levers 12, 12', 12'', etc., are stacked one above the other on rod 14. The latter is constrained by spring 10 to move away from the center of the storage disk. Associated with each lever is a spring 16, 16', 16'', etc., which urges its corresponding lever toward the center of the disk surface. Such motion is inhibited by armature 18 of electromagnet 20.

Adjacent to the inner ends of the levers is a stack of cam disks 20, 22, 24, and 26 mounted on rod 14. Each cam is equal in shape and has four notches 28 connected by curves. By stacking eight cam disks on top of each other and displacing them angularly by an angle of 11.7 degrees between adjacent disks, there is obtained a stack with thirty-t...