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)

2 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. Goal of V&V of COTS RTOS Center Initiative

3 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.

4 Current Embedded OS Usage EE Times conducted a series of surveys over the years on the operating systems used by its readers.

5 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

6 Products in development –VxWorks RTOS Test 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

7 V&V of COTS RTOS Center Initiative Test Case Status

8 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.