Software maintainability for the Space Station information system

Because the useful life of the Space Station Freedom (SSF) is estimated to be at least 30 years, software maintenance is a driving factor in the specification and design of the system. Once the fundamental character of software maintenance has been designed, no amount of management during the maintenance phase can, in general, overcome built-in problems. To address this problem, the SSF Program Office has identified a number of design drivers and a corresponding collection of standards that will be used in the design of the information system. In the area of communications standards, a new international standard has been proposed and adopted by the consultative committee for Space Data Systems. In the area of operating systems, the POSIX family of standards has been chosen. X-Windows, the de facto standard for windowing services for Unix systems, has been specified as part of the application-layer protocol. Finally, in the area of database standards, a collection of SQL-based standards has been adopted