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Finite State Machine DEAT/TREAT Algorithm

IP.com Disclosure Number: IPCOM000019241D
Publication Date: 2003-Sep-08

Publishing Venue

The IP.com Prior Art Database

Abstract

Disk drive rotational position optimization (RPO) algorithms use DEAT or TREAT tables to determine expected access times for commands. With DEAT the expected access time (EAT) calculation requires one divide and one multiply for each command in the queue. With TREAT the updating of table elements requires a fraction part to table elements if previous algorithms are used. The new algorithm presented here cuts the DEAT table space by 50% and eliminates both the divide and the multiply. No additional table space is required for EAT calculations or DEAT updates. With TREAT the new algorithm provides for an efficient update without the requirement of a fractional part to the table elements.