Patent ID: 6986132

Claim:
A method of operating a computer system, said method comprising: providing a first version of a program in memory, said first version of a program including at least one program unit, each program unit comprising an Application Programing Interface (API) definition file and an implementation, each API definition file defining items in its associated program unit that are made accessible to one or more other program units, each implementation including executable code corresponding to said API definition file, said executable code including type specific instructions and data; and performing a first verification including verifying said program prior to execution of said program, said first verification including indicating a verification error when a first version of a first program unit implementation is not internally consistent; indicating a verification error when said first version of said first program unit implementation is inconsistent with a first version of said first program unit API definition file associated with said first version of said first program unit implementation; receiving a second version of said first program unit implementation and a second version of said first program unit API definition file, said second version being a revised version of said first version; performing a second verification including verifying said second version of said first program unit implementation, including indicating a verification error when said second version of said first program unit implementation is not internally consistent; and indicating a verification error when said second version of said fist program unit implementation is inconsistent with said second version of said first program unit API definition file; and performing a third verification including verifying said second version of said first program unit implementation is binary compatible with said first version of said first program unit implementation by comparing said first version of said first program unit API definition file and said second version of said first program unit API definition file.