A method to update code in an information storage and retrieval system comprising one or more processors, and existing code, where that existing code includes a Concurrent Code Load having (N) phases, where that Concurrent Code Load invokes an as yet unwritten Temporal Coupling File. The method provides a code update image comprising that Temporal Coupling File. If the (i)th phase of the Concurrent Code Load invokes the Temporal Coupling File, then the method reads instructions for that (i)th phase of the Concurrent Code Load from the Temporal Coupling File, and executes those instructions. The method completes each phase of the Concurrent Code Load, and then operates the system using the code update.