The Need For Vendor Source Code at NAS

The Numerical Aerospace Simulation (NAS) Systems Division has a long standing practice of maintaining buildable source code for installed hardware. There are two reasons for this: NAS' designated pathfinding role, and the need to maintain a smoothly running operational capacity given the widely diversified nature of the vendor installations. NAS has a need to maintain support capabilities when vendors are not able; diagnose and remedy hardware or software problems where applicable; and to support ongoing system software development activities whether or not the relevant vendors feel support is justified. This note provides an informal history of these activities at NAS, and brings together the general principles that drive the requirement that systems integrated into the NAS environment run binaries built from source code, onsite.