Space Shuttle GPCF: A Retrospective Look

This paper is based on a recent experience implementing and testing a large new software capability in a maintenance organization which had not dealt with a large change in some time. The capability was called GPC Payload Command Filter (GPCF). While the task was completed successfully, it was not without cost in terms of schedule slips and personal angst. The purpose of this paper will be to help the verifier learn from what was done right and what was done wrong, hopefully to avoid the pitfalls and emulate the successes. Specifically, the objective is as follows:
To provide guidance on how to successfully test a large new software capability using verification processes which have specialized over time to provide extremely effective results
for relatively small changes.