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V&V of COTS RTOS for Space Flight Projects The 1st Annual NASA Office of Safety and Mission Assurance (OSMA) Software Assurance Symposium (SAS) Michael Rahmatipour MSFC. Contact Information: MSFC Avionics Department Flight Software Group (ED14) 256-544-5115
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V&V of COTS RTOS for Space Flight ProjectsThe 1st Annual NASA Office of Safety and Mission Assurance (OSMA) Software Assurance Symposium (SAS)Michael RahmatipourMSFC Contact Information: MSFC Avionics Department Flight Software Group (ED14) 256-544-5115 Michael.H.Rahmatipour@msfc.nasa.gov
Goal of V&V of COTS RTOS Center Initiative • The main goal is to perform V&V of the RTOSs used in critical flight applications in the following steps: • Evaluate the amount of software testing performed by vendors of CTOS RTOS. • Develop a set of generic test requirements for embedded flight real-time operating systems. • Develop a test plan and approach to perform V&V on a candidate operating systems against the above generic requirements. • Develop test software and test procedures to implement the verification plan.
Purpose of the V&V of COTS RTOS Center Initiative • Multiple, space-related programs currently use commercial off-the-shelf (COTS) real-time operating systems (RTOSs) as part of the NASA goal to reduce software development time and cost. • Recent, high-profile NASA mission failures have underscored the need for highly reliable software. • An internal NASA audit showed a need for verification and validation (V&V)/certification tests of the COTS RTOSs used. • These operating systems should be tested to the same confidence level as flight critical software applications.
Current Embedded OS Usage EE Times conducted a series of surveys over the years on the operating systems used by its readers.
V&V of COTS RTOS Center Initiative Products and Status • Completed deliverables • White paper on current practices for vendor V&V of commercial operating systems. • Software Requirements Specification for a Reusable Realtime Operating System for Embedded Systems. • Software Requirements Specification for the VxWorks RTOS for Embedded Systems. • Plan and Approach for V&V of the VxWorks Realtime Operating System. • Plan for Verification of the VxWorks Realtime Operating System.
V&V of COTS RTOS Center Initiative Products and Status • Products in development • VxWorks RTOSTest procedures and test reports • MSFC is developing the test software and procedures to verify the Software Requirements Specification for the VxWorks RTOS for Embedded Systems • There are 157 requirements that are organized in 28 cases. • Final Software Requirements Specification for the VxWorks RTOS for Embedded Systems
V&V of COTS RTOS Center Initiative Summary • There are many good packages available as real-time kernels. • The level of effort required by end users to verify/validate or certify a RTOS is highly dependent on the processor board, contents of the software executable, development and source code documentation (including requirements), and tools available for verification. • Any V&V/certification effort will be valid for the tested configuration only. Any update to the processor board, peripherals, RTOS, etc. will necessitate a re-verification. • An important consideration in choosing a COTS RTOS for a safety critical application is the degree of support the vendor will provide for a verification effort.