Cache control protocols can be switched during running without changing an architecture for a segment descriptor or page descriptor for indicating an attribute of an area to be accessed. A plurality of processors each including a cache memory constitute a multiprocessor system which shares a main memory via a system bus. Each processor has module detecting means for detecting execution of a module which accesses a shared memory area on the main memory, by comparing the virtual space number and the instruction segment number concerning the accessing module with those numbers concerning the software modules preset which may access the shared memory area. Memory access executed in a module detected by the module detecting means is controlled in a cache control protocol of a store-through scheme which updates a main memory simultaneously with update of a cache memory. Memory access executed in other modules is controlled in a cache control protocol of a store-in scheme which does not update a main memory at update of a cache memory.
A system for delivering data objects containing data subject to periodic updates to a plurality of clients is disclosed and which is configured to connect to at least one input data stream which carries a specific type of data objects, such as objects related to financial product offerings, and also establish a communication session with various clients. Each client has an associated profile which indicates data stream to which the client has subscribed and further contains rules related to how data in the streams should be treated. When an object is received on a data stream, a local data cache is updated and the rules specified by clients subscribing to that data stream are executed to determine whether information about the object should be forward to the various subscribing client. In a particular configuration, the data channels are provided by one or more information managers which pre-process raw data from source data providers, format and type the data, and broadcast it on appropriate channels in substantially real time.
