after performing the operations the os has either faulted due to a feature mismatch or has completed the exchange of all feature words if a fault did not occur both the os and spp have identical records of which features are mutually supported in their respective arrays if an optional feature is not supported it will not be used and an alternative mode of operation may be effected it is appreciated with respect to fig1 and 4 that the features_os array is an implementation of the features list 23 and the hardcoded bit masks are stored at 24 the supportedfeatures_os array is an implementation of the supportedfeatures list 30 with the bit masks stored at 31 the features_spp array is an implementation of the features list 40 with the hardcoded bit masks stored at 41 the supportedfeatures_spp array is an implementation of the supportedfeatures list 50 with the bit masks stored at 51 the sppfeatures_os is returned as report 22 bit masks are utilized to facilitate the comparison operation the use of bit masks is not however a requirement other known feature indication storage arrangements such as any bit map arrangement could be utilized to the same effect another example of two software entities that may utilize the invention are two independent processes running within the same computer system controlled by the same os any two software.