Browse Prior Art Database

Head To Track Synchronizing Mechanism for Magnetic Disks

IP.com Disclosure Number: IPCOM000086524D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 46K

Publishing Venue

IBM

Related People

Porter, TH: AUTHOR [+2]

Abstract

Synchronization between magnetic head 30 and various inner data tracks 1, 2, 3..n on magnetic disk 32 is obtained by prewriting a sync track 34 (at track location zero) adjacent the edge of disk 32. Circuit 36 is used to determine the center of track 34 and to count. A stepping motor 38 drives head 30 to reach the various inner data tracks 1, 2, 3..n.

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Head To Track Synchronizing Mechanism for Magnetic Disks

Synchronization between magnetic head 30 and various inner data tracks 1, 2, 3..n on magnetic disk 32 is obtained by prewriting a sync track 34 (at track location zero) adjacent the edge of disk 32. Circuit 36 is used to determine the center of track 34 and to count. A stepping motor 38 drives head 30 to reach the various inner data tracks 1, 2, 3..n.

Magnetic disk 32 within a jacket 40 constitutes an assembly, as described in
U. S. Patent 3,668,658 which issued June 6, 1972. Jacket 40 and disk 32 are positioned in a disk drive machine using conventional guiding means, and disk 32 is rotated by motor driven means contained in the disk drive machine. Magnetic head 30, which is of the single-gap type, is mounted on arm 42 which is swingably mounted by means of rotatable shaft 44. Gearing 46 connects motor 38 to shaft 44 and arm 42. Gearing 46 comprises gear sector 48 fixed on shaft 44, pinion gears 50, 52 and 54 and spur gears 58 and 60 meshing with each other and with sector 48.

After disk 32 and cartridge 40 have been inserted in place in the disk drive machine, head 30 is lowered onto the disk 32 outside of the sync or 0 track 34 in a head landing area 62. A series of electrical pulses are then applied to the stepping motor 38, and head 30 is stepped toward sync track 34 to find its center. Circuit 36 is used for finding the center of sync track 34 and monitoring the sync track signal electronically to determine peak output. Circuit 36 includes amplifier 64 connected with head 30, amplitude sense circuit 66, sample-and- hold circuits 68 and 70, and comparator 72. As successive pulses are applied to stepping motor 38, sample-and-hold circuits 68 and 70 sample successive outputs of head 30, and particularly the amplitudes of the head outputs using circuit 66. As the center of track 34 is approached, the amplitudes held by circuits 68 and 70 increase. When the samples held by the two circuits 68 and 70 are substantially the same, as indicated by comparator 72, the substantial center of sync track 34 is indicated.

Thereafter, any of the successive inner data tracks 1, 2, 3..n may be reached by head 30 simply by applying the appropriate numbers of additional pulses to stepping motor 38. For example, if 16 pulses applied to stepping motor 38 are effectively between each of the sync and data tracks on disk 32, a multiple of the 16 pulses may be used to move head 30 to any of the data tracks from the sync track 34.

Thus, if it is desired that head 30 reach the fifteenth data track, 15 times 16 pulses are applied to stepping motor 38 to cause head 30 to make this excursion.

The head 30 may be used for both writing and...