Method and apparatus for modifying microcode in a distributed nodal network while the network continues operation

摘要

Updating of control code is accomplished in multiple nodes of a computing system while the computing system remains in operation. Each node includes a processor, memory, a first version of a control code unit and an engineering change level indication for the control code unit. The method comprises the steps of: installing a revised version of the control code unit with converter code modules in a first node, the converter code modules enabling and performing first and second interface functions during communications between the first node and other nodes in the system. The first node is then operated to perform a function which requires communication with other nodes, the converter code module in the first node initially determining an engineering change level value stored in another node and, if the engineering change level values in the nodes match, communicating with the other node through the first interface function. If the engineering change level values are found not to match, communications occur with the other node through the use of the second interface function, enabling both nodes to communicate even though different level code changes are present. A sequencer is also provided in the computing system which enables updating of all nodes in a specified sequence so as to simplify the requirements placed upon the converter code module.