Method and apparatus for performing non service affecting software upgrades in place

An apparatus comprising a processor for upgrading software represented as a call flow graph having a plurality of states and a plurality of state transitions where a plurality of tokens traverse the graph executing functions, the apparatus comprises:

• means for identifying a target region of the graph;
• means for obtaining a new region for the graph;
• means for determining a correspondence between states of the target region of the graph and states of the new region for the graph, said means for determining the correspondence between states of the target region of the graph and states of the new region for the graph further comprising:
• means for identifying states of the target region of the graph;
• means for identifying states of the new region for the graph;
• and
• for each of the identified states of the target region of the graph, means for determining whether any of the states of the new region for the graph are associated with that state of the target region of the graph;
• and
• means for replacing the target region of the graph with the new region for the graph using the correspondence between states of the target region of the graph and states of the new region for the graph.

A non-transitory computer readable medium storing a software program that, when executed by a computer, causes the computer to perform a method for upgrading software represented as a call flow graph having a plurality of states and a plurality of state transitions where a plurality of tokens traverse the graph executing functions, comprising:

• identifying a target region of the graph;
• obtaining a new region for the graph;
• determining a correspondence between states of the target region of the graph and states of the new region for the graph, said step of determining the correspondence between states of the target region of the graph and states of the new region for the graph comprising:
• identifying states of the target region of the graph;
• identifying states of the new region for the graph;
• and
• for each of the identified states of the target region of the graph, determining whether any of the states of the new region for the graph are associated with that state of the target region of the graph;
• and
• replacing the target region of the graph with the new region for the graph using the correspondence between states of the target region of the graph and states of the new region for the graph.