Abstract:
An optical disc which serves both as a program disc and as a data disc by utilizing the fact that an optically recording/reproducing disc (1) has a very large capacity. Namely, onto a predetermined region (5) of the disc non-rewritably recorded in advance are a software program necessary for processing the data recorded in the optical disc (1) or the basic data necessary for executing the program, as well as an erasing program for executing the erasing operation for the recording region. Even in case the software programe and the basic data for executing the program are copied without authorization, the copy disc is prevented from being used.
Abstract:
An optical data recording and reproducing apparatus which records and reproduces data in sector units with respect to an optical recording disc provided with an optically detectable guide track that is divided into a plurality of regions to provide a sector structure. A recording signal for each sector is constituted by a group of a plurality of data record units (frames), and each frame is constituted by data (11) and a data mark (10) identifying the head of the data, to reduce any erroneous propagation of demodulated data supplied into a memory due to, for example, a dropout in the optical recording disc during the reproduction of a sector. A frame number (22) is added to each frame and recorded. During reproduction, demodulated data is supplied to a memory address in the memory corresponding to the readout frame number, to prevent erroneous supply of demodulated data when a data mark is missing.
Abstract:
A method and apparatus for disc authentication are disclosed. The authentication method includes measuring at least one physical property of a data disc, which includes at least one of an angle and an eccentricity parameter associated with two data layers of a data disc, and authenticating the disc by determining whether a match exists between the measured property and encoded information on the data disc relating to the physical property.
Abstract:
Die Erfindung betrifft eine Mastervorrichtung, verwendbar im Verfahren zur Herstellung eines Aufzeichnungsmediums, wobei auf der Mastervorrichtung eine im Wesentlichen spiralförmig oder konzentrisch verlaufenden Hauptspurstruktur und wenigstens eine im Wesentlichen spiralförmig oder konzentrisch verlaufenden Nebenspurstruktur ausgebildet ist, wobei die Nebenspurstruktur wenigstens auf einer Seite der Hauptspurstruktur angeordnet ist, und die Nebenspurstruktur Unterbrechungen aufweist, die eine optische erfassbare Oberflächenbeschaffenheit des Aufzeichnungsmediums derart variieren, dass auf dem Aufzeichnungsmedium wenigstens eine erste Hilfsinformation abgebildet wird.