Browse Prior Art Database

Shortcut Error Recovery Procedure

IP.com Disclosure Number: IPCOM000014529D
Original Publication Date: 1999-Dec-01
Included in the Prior Art Database: 2003-Jun-19
Document File: 3 page(s) / 65K

Publishing Venue

IBM

Related People

Masahiko Sato: AUTHOR [+3]

Abstract

Disclosed is a procedure to reduce the time to spend for the error recovery during reading or writing data on a hard disk drive so that the decrease of the data transfer rate between the hard disk drive and the host system is minimized. The firmware of the hard disk drive has a certain error recovery procedure, which consists of several steps for several different kinds of errors like Thermal Asperity, Off-tracked data, etc. The error recovery procedure accesses the data with many different ways from the normal access Each way is defined as an error recovery step and it is performed in a pre-defined order. Once an error occurs and is recovered by a certain step, this Shortcut Error Recovery Procedure stores the information of the error recovery which consists of the error location, read or write, what kind of error, which step has recovered the error. Next time the same error occurred at the same location, the Shortcut Error Recovery Procedure attempts the error recovery step first which was stored at the previous same error. This may reduce the time to recover an error that is repeatable and minimize the decrease of the data transfer rate.

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Shortcut Error Recovery Procedure

    Disclosed is a procedure to reduce the time to spend for the error recovery during reading or
writing data on a hard disk drive so that the decrease of the data transfer rate between the hard
disk drive and the host system is minimized. The firmware of the hard disk drive has a certain error
recovery procedure, which consists of several steps for several different kinds of errors like
Thermal Asperity, Off-tracked data, etc. The error recovery procedure accesses the data with many
different ways from the normal access Each way is defined as an error recovery step and it is
performed in a pre-defined order. Once an error occurs and is recovered by a certain step, this
Shortcut Error Recovery Procedure stores the information of the error recovery which consists of the
error location, read or write, what kind of error, which step has recovered the error. Next time the
same error occurred at the same location, the Shortcut Error Recovery Procedure attempts the error
recovery step first which was stored at the previous same error. This may reduce the time to recover
an error that is repeatable and minimize the decrease of the data transfer rate.

For example, let's think a case of reading a sector. A sector has data written on off-track position
which cannot be read on on-track position. To read data from the sector, the head of the hard disk
drive should seek to a certain off-track position but the off-track read error recovery step may be
the tenth step of the conventional error recovery procedure for Read operation. First time the sector
written on off-track is read, the Shortcut Error Recovery Procedure checks on the stored information
whether the same error has occurred on the same location before. Since there is no information for
the error, the conventional error recovery procedure does the error recovery step by step from the
first step. Only one error recovery step can be done to the sector per one revolution of the disk.
Therefore ten revolutions are needed to reach the tenth step for the sector to be able to be read.
The Shortcut Error Recovery Procedure stores the information of the error recovery which consists of
Logical Block Add...