Reducing rigid-body rotational vibration is essential for achieving high-accuracy, high-speed head positioning for hard disk drives. A reaction-force isolated, damped VCM-supporting mechanism has been prototyped to suppress base excitation due to reaction force. The mechanism consists of VCM-yoke sliding surface and viscous-elastic material. Using the mechanism, the vibration acceleration at the edge of the base after head-positioning has been reduced by 31% and the residual vibration of the position error signal has been reduced by 27%. The results prove that this mechanism is favorable for achieving high-accuracy, high-speed head positioning for hard disk drives.

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In recent years, highly and multi functional technologies are rapidly brought to the field of wristwatch and have been paid much attention. Citizen has developed highly and multi functional watches applying latest electronics technology and put them into market, mostly sports watch market. To realize the advanced highly and multi functional technologies as well as low power consumption in a watch, we have developed PGM system which carries embedded real-time OS. Cyber Aqualand (Cal.D700) is our first product that realized PGM system on it. Cal.D700 is an advanced product of Hyper Aqualand. It is a dive computer watch communicable with PC using wireless communication system. Furthermore, Cal.D700 carries secondary battery that can be recharged so that it cleared the annoyance for those who dive frequently and have to change the batteries in a short period of time.

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Hard disk drives (HDD : Hard Disk Drive) play an important role in advanced information society. They are widely used in various fields as external memory devices for personal computers, network computers, super technical servers, and so on. They are also used in the new applications, such as car navigation systems, video recorders, and removable devices. The series of three articles to be presented here focus on the structural aspect of HDDs. To help readers understand HDDs well, the history of HDDs, the uses and roles of HDDs, and the performance of currently manufactured HDDs are explained in Part 1. The structure of HDD and its elements will be shown in Part 2. Structural technology to achieve high-speed, high-accuracy head-positioning and future prospect will be described in Part 3.

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