PERSISTENT STATE CHECKPOINT AND RESTORATION SYSTEMS

摘要

A checkpoint and restoration system (10) provides restoration techniques for user application processes which save the volatile state and portions of the persistent state, during execution, and thereafter restore the saved state. A lazy checkpoint technique delays the taking of the persistent state checkpoint until inconsistency between the checkpointed volatile state and the persistent state is about to occur. The checkpoint and restoration system (10) allows a user or user application process (40) to specify portions of the persistent state to be excluded from a checkpoint. A selected portion of the pre-restoration process state, such as a return value argument, may be protected before restoring the user application process to a checkpointed state, so that pre-restoration values of the protected state are retained following restoration. The retained return value allows segments of restoration code to be executed following a restoration and allows a normal execution mode to be distinguished from a restoration mode.