Abstract: The present invention relates to a record carrier (10) for storing user data in sectors (S) and management information (n) associated with said sectors. In order to provide a simple, low-cost, flexible and secure copy protection of the user data when being transmitted over a communication bus (6) of a PC it is proposed according to the present invention that the management information comprises an encryption indication information (M1) indicating that the user data stored in the associated sector (S) are to be encrypted by a read-out device (2) before being transmitted over a communication bus (6).

Abstract: An apparatus for recording information signals in a track (T.sub.i) on a record carrier (2) is disclosed, comprising an input terminal (30) for receiving an information signal, a signal processing unit (32) for processing the information signal so as to make the information signal suitable for recording in at least one track on said record carrier, and a writing unit (33) for writing, after processing, the information signal in said at least one track on said record carrier, starting from a start position (s) viewed in the length direction of the record carrier and in a direction towards one of the end positions of the record carrier.The portion of the record carrier (2) between said start position (s) and said one end position (L.sub.2) is fictitiously divided into a first sub portion lying (P.sub.1) adjacent the start position and a second sub portion (P.sub.2) lying adjacent the end position of the record carrier.

Abstract: Service items at a central authority are scheduled as to their selective availability upon user request at remote stations. These are bidirectionally connected to the central authority. Each service item is assigned to one or more structures of items. Each structure of items is assigned to one or more of a set of navigation contexts. One unique start instant in absolute time is assigned to each respective navigation context. Upon attaining of any such start instant, all service items assigned to the associated navigation context are rendered available unto a detected request.

Abstract: The invention describes the organizing and accessing of data pertaining to an engineering process. The process is partitioned into subprocess which are linked in a directed-acyclic-graph. Each link has a source node and a destination node, indicating which source node(s) must have been executed to provide the data necessary for executing the destination nodes. Executing any subprocess provides an instance of data associated to that node. The latter instances are linked in a second directed-acyclic-graph wherein each link indicates that part or all of the data at the source node has effectively been used for generating the data at its destination node. The two graphs are interlinked and provide for easy browsing of the data as well as for easy selection of input data for engineering subprocesses.