HIGH-PERFORMANCE ADAPTIVE-SPEED CAV CD-ROM DRIVE/

This paper describes a novel type of CD-ROM drive which can automatica lly distinguish between two basic operating modes: continuous playback and continuous access. The drive, based on the adaptive-speed technol ogy, is optimized for a very high data throughput during sustained rea d-out using a new cubic overspeed profile. In addition, by detecting t he state of continuous access and switching the spindle motor into a C AV (constant angular velocity) loop, the drive features very low power consumption. Two dedicated firmware algorithms which can detect one o f the two operating modes either at the bit-engine level or at the dat a-path level are also presented. While implementing the algorithm at t he data-path level, the paper will also approach a novel technique for the optimization of the data flow via controlling the speed of the sp indle motor. A better buffer management can therefore be achieved. Las t but not least, the cubic overspeed profile is shown to be optimal no t only for sustained playback but also while the drive is performing e ither a unique seek action or a short sequence of seeks.