Region detection system for detecting empty sectors on a recording medium

Abstract

A region detection system for detecting empty sectors on a recording medium, such as an optical disk, suitable for use in a optical disk unit, reads out data from a sector to determine whether the sector is empty. To determine whether a sector is dataless, the sector is read out to reproduce signals which include predetermined signals, such as block synchronizing signals or RF signals, by which the length of data recorded can be recognized. The predetermined signals are detected and a cumulative count is kept. The cumulative count for the region is compared with a predetermined reference value, and the region is recognized as dataless (empty) when the cumulative total is not larger than the reference value, while the region is considered to contain data when the cumulative value exceeds the reference value. In a further embodiment, the reproduced signals are sample by a detector at predetermined intervals, and the cumulative total is increased when the predetermined signals occur at successive intervals. Preferably, the reference value is selected so that it is no larger than a maximum length in which errors can be corrected.

Dependencies are inferred from the claim text.