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Browse Prior Art Database

Apparatus for Detecting and Correcting Excessive Vibration in a Disk File

IP.com Disclosure Number: IPCOM000040392D
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Ottesen, HH: AUTHOR

Abstract

The apparatus detects excessive vibration in a DASD (direct access storage device) or magnetic disk file A by means of accelerometer 1 coacting with level detector 3 which actuates actuator servo channel 5 to produce more temporary damping of file A. Detection of severe external vibrations and shocks can be accomplished by placing one or more accelerometers, such as accelerometer 1, in strategic positions in disk enclosure 2 and particularly on the DASD casting. The purpose is to avoid situations in which the file is most vulnerable, namely in the write mode. If a severe mechanical shock happens during the write operation, it is likely that the track misregistration (TMR) would be so large that writing into the adjacent track would occur. This could cause permanent damage to the adjacent track data information i.e.

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Apparatus for Detecting and Correcting Excessive Vibration in a Disk File

The apparatus detects excessive vibration in a DASD (direct access storage device) or magnetic disk file A by means of accelerometer 1 coacting with level detector 3 which actuates actuator servo channel 5 to produce more temporary damping of file A. Detection of severe external vibrations and shocks can be accomplished by placing one or more accelerometers, such as accelerometer 1, in strategic positions in disk enclosure 2 and particularly on the DASD casting. The purpose is to avoid situations in which the file is most vulnerable, namely in the write mode. If a severe mechanical shock happens during the write operation, it is likely that the track misregistration (TMR) would be so large that writing into the adjacent track would occur. This could cause permanent damage to the adjacent track data information i.e., unrecoverable (hard) data errors. For the same external conditions, only soft errors would occur during a read mode. If an accelerometer detects a shock/vibration disturbance exceeding a certain level, then a write operation could be aborted until it is safe to proceed. The operator could be notified if the vibratory condition exceeds a certain time limit. As a result, the system, which is assumed to have a retry operation in the read mode in case of a read error, will now also have a retry operation in the write mode. The figure 1 shows a conceptual view of the apparatus using a single accelerometer 1 mounted to the disk enclosure 2 for best sensitivity. The accelerometer output is fed into...