1. A method for controlling the execution of a user application process following the restoration of a checkpointed state, said user application process having a process state, said method comprising the steps of: checkpointing at least a portion of the process state at a first execution point; restoring the process state to said checkpointed state at a second execution point, said restored process state retaining a pre-restoration value of at least one variable; resuming execution of the user application process using the restored process state; and performing one or more instructions in said user application process based on the retained pre-restoration value.