Patent ID: 8418163

Claim:
A stacked hardware abstraction layer method for maintaining software/hardware backward compatibility for networking equipment and the like, the method comprising: given application software and a hardware abstraction layer associated with a newer release and a device comprising firmware associated with an older release, providing one or more shadow hardware abstraction layers for each intervening release, wherein a loading interface of the firmware is supported by each of the one or more shadow hardware abstraction layers, and wherein the hardware abstraction layer comprises an interface between the application software and the firmware enabling the application software to interface to the firmware at an abstract level; transferring messages that are supported by the older release between the application software and the device through the one or more shadow hardware abstraction layers; filtering messages that are not supported by the older release and not transferring the messages between the application software and the device at the one or more shadow hardware abstraction layers; and thereby upgrading the firmware of the device to the newer release.