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ROTATIONAL POSITIONING OPTIMIZATION WITH LOOK A HEAD ALGORITHM

IP.com Disclosure Number: IPCOM000013183D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2003-Jun-17

Publishing Venue

IBM

Abstract

Disclosed is a method to improve performance for Tagged Queue Command Reordering using a combination RPO (Rotational Positioning Optimization) and LookAhead cache. When only RPO is implemented to the hard disk drive it must care Seek time, Overhead time, Rotational latency ti preparation for Seek and Tagged Queue Command Reordering) If the host orders to process several read commands, a two commands are continuous sectors, the drive with RPO never choose the second command as a shortest access tim However to choose the second command makes the drive with LookAhead cache performed better throughput because th must be hit on LookAhead cache data by the first command. The following figure explains about how to find the ne all queued command by RPO and LookAhead cache. FIGURE:( used pseudo code Find next queue (Next_Queue) from current queue (Current_Queue) both in Queue table (Q_TABLE)