Definitions

Shoeshine Effect, Reed-Solomon code and Fly Height

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Shoeshine effect: The effect that happens when a host transmits data to a tape drive more slowly than the tape drive can write the data (its sustained data transfer rate). This results in a tape drive that stops, backs up and starts again--hence the shoeshine analogy. Shoeshine should be avoided, as it exposes the drive's R/W head and the media to experience abnormal wear and tear. Options include upgrading the host or choosing a slower...

tape drive.

Reed-Solomon code:
Block-based error correcting codes with a wide range of applications in digital communications and storage. The Reed-Solomon encoder takes a block of data and adds extra redundant bits. If an error occurs during transmission, the Reed-Solomon decoder processes each block and attempts to correct errors and recover the original data. The number and type of errors that can be corrected depends on the Reed-Solomon code characteristics.

Fly height:
In a disk drive, the distance from which heads fly above the hard disk platters. For engineers, this is an important design characteristic. If the fly height is too far from the surface, data errors can occur. But if the head flies too close, chances of a head crash increase dramatically.

This was first published in February 2003

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