1. A method in a data processing system for making a system call by a program executing on the data processing system, comprising: the data processing system receiving the system call from the program, the system call comprising a parameter that includes an input process identification; responsive to the receiving of the system call, the data processing system mapping the input process identification to a real process identification that identifies a process executable by the data processing system; and responsive to the mapping of the input process identification to the real process identification, the data processing system passing the real process identification in lieu of the input process identification as the parameter of the system call, wherein the step of mapping the input process identification to the real process identification comprises: the data processing system receiving a first process entry for a first process in a group from a process table comprising process information for processes existing in the data processing system; and the data processing system determining whether the input process identification is equal to a virtual process identification stored in the first process entry, wherein the virtual process identification is a previous process identifier for a previously checkpointed process; and the data processing system outputting a corresponding real process identification in response to the input process identification being equal to the virtual process identification.