Network system, control method, control apparatus, and multiprocessor

A control method in a control apparatus capable of sharing data with a plurality of control apparatuses connected to a network, wherein:

• when a user program provided in said control apparatus accesses data stored in a memory portion,
• correlation information correlated with memory position information where said data is stored and with logical names assigned to the data is stored;
• said user program acquires said correlation information based on the logical names, and accesses said memory portion, and
• said correlation information is stored separately in an indirect reference table which stores memory position information used for accessing data stored in the memory portion, and a correspondence table having a correspondence with the memory position information inside said indirect reference table storing the logical names and the memory position information for the logical names.

A control apparatus capable of sharing data with other control apparatuses connected to a network, comprising:

• a communication portion which carries out data exchange with said other control apparatuses through the network;
• a memory portion which stores shared data acquired by said communication portion, wherein said shared data are defined by logical names;
• a correlation information memory portion which stores correlation information correlated with the logical names and memory position information of said memory portion storing data corresponding to the logical names;
• a control execution portion having a function which accesses said correlation information memory portion based on said logical names, acquires said position information corresponding to the logical names and accesses memory regions of said memory portion storing corresponding data;
• and
• updating means which update said correlation information of said correlation information memory portion based on changes of said position information inside said memory portion, wherein said correlation information memory portion is provided with an indirect reference table which stores the memory position information used for accessing data stored in the memory portion, and a correspondence table having a correspondence with the memory position information inside said indirect reference table storing the logical names and the memory position information for the logical names.

A multiprocessor system in which occupied local memories possessed by a plurality of processors are connected by a bus, comprising:

• a data transfer process portion which periodically carries out data exchange between each of said local memories;
• an indirect reference table used for accessing data stored inside the local memories;
• a control execution portion which possesses a mechanism for accessing data through said indirect reference table;
• and
• a logical name adjustment portion which controls a correspondence table of logical names and local memory addresses and changes said indirect reference table;
• and wherein correlation information is stored separately in said indirect reference table storing memory position information used for accessing data stored in said local memories, and the correspondence table having a correspondence with the memory position information inside said indirect reference table storing the logical names and the memory position information for the logical names.