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Periodic and Sampling Servo System for Disc Drive

IP.com Disclosure Number: IPCOM000043983D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Kisaka, M: AUTHOR

Abstract

In this servo system, track servo operation is periodically carried out by positioning a transducer head precisely to a predetermined track of a cylinder group which consists of a number of neighboring cylinders. In that operation, the compensation amount for head positioning deviation from the predetermined track is stored in some storing means. After that, when the transducer head accesses any one of tracks of the cylinder group, the stored compensation amount is used for compensating for head positioning deviation from the accessed track of the group. The stored compensation amount is used until the next track servo operation is carried out in the group. Likewise, this periodic and sampling servo operation is carried out to the other cylinder groups. The following are details of the servo system. As shown in Fig.

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Periodic and Sampling Servo System for Disc Drive

In this servo system, track servo operation is periodically carried out by positioning a transducer head precisely to a predetermined track of a cylinder group which consists of a number of neighboring cylinders. In that operation, the compensation amount for head positioning deviation from the predetermined track is stored in some storing means. After that, when the transducer head accesses any one of tracks of the cylinder group, the stored compensation amount is used for compensating for head positioning deviation from the accessed track of the group. The stored compensation amount is used until the next track servo operation is carried out in the group. Likewise, this periodic and sampling servo operation is carried out to the other cylinder groups. The following are details of the servo system. As shown in Fig. 1, the disc file has several cylinder groups 1 and 2 consisting of a number of neighboring cylinders. Each track in the cylinder has servo data patterns T1 and T2 thereon, as shown in Fig. 2. When the transducer head 4 passes through the servo data patterns T1 and T2, servo data T1 and T2 are detected by the head 4 and their signal intensities are compared to each other by the circuit in Fig. 3. If the head 4 is exactly positioned at the center of the track N, both signal intensities of T1 and T2 are equal. If the head 4 is above (below) the track N, the signal intensity of T1(T2) is larger than that o...