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Head recovery procedure enhancement

IP.com Disclosure Number: IPCOM000014583D
Original Publication Date: 2000-May-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 1 page(s) / 26K

Publishing Venue

IBM

Abstract

Disclosed is device firmware that new method of device head recovery. Current head recovery procedure is passive recovery procedure that means the recovery procedure is performed if error(s) are occurred. It takes much time for recovery. This is main cause of system timeout. New method is active recovery procedure, firmware keeps watching head condition and performs recovery procedure if the condition get worse. Therefore system timeout issue will be reduced.

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Head recovery procedure enhancement

Disclosed is device firmware that new method of device head recovery. Current head recovery
procedure is passive recovery procedure that means the recovery procedure is performed if
error(s) are occurred. It takes much time for recovery. This is main cause of system timeout. New
method is active recovery procedure, firmware keeps watching head condition and performs recovery
procedure if the condition get worse. Therefore system timeout issue will be reduced.

Now HDD supports load/unload function. Some error recovery procedure includes load/unload
operation and it takes time, but this kind of recovery steps have more effectiveness than shorter
one. Basic idea of this new recovery method is performing this error recovery step during device
idle.

During recovery procedure, firmware judges next step by checking device condition. New recovery
method checks device condition if a device enters idle mode (power save mode), then judges
whether effective (but taking time) recovery procedure should be performed or not. This method
has 2 merits to reduce time for recovery procedure: One is a device can skip load or unload
operation. For example, some error recovery procedure should be performed on a ramp, this means
unloaded condition. Normally during read or write operation, heads fly above disks, this means
loaded condition. Therefore the heads should be unloaded for this kind of error recovery
procedure. But if this step performs during low power id...