The cost to re-certify previously approved software is a function of the amount of change. Changing just a single line of a single module and then re-compiling/re-linking the whole system results in an entirely new executable which then must be evaluated in whole. Deos, a time and space partitioned RTOS, certified to DO-178B Level A since 1998, solves this problem through Binary Partitioning. This allows developers to constrain the change to the single module, thus drastically reducing the amount of recertification required. This capability which is unique to Deos, allows mission critical systems to evolve and innovate at a faster rate with much lower recertification cost each time a modification is required. This paper describes some of those key Deos technologies.