Behavioural properties and dynamic software update for concurrent programmes

Software maintenance is a major part of the development cycle. The traditional methodology for rolling out an update to existing programs is to shut down the system, modify the binary, and restart the program. Downtime has significant disadvantages. In response to such concerns, researchers and practitioners have investigated how to perform update on running programs whilst maintaining various desired properties. In a multi-threaded setting this is further complicated by the interleaving of different threads' actions. In this thesis we investigate how to prove that safety and liveness are preserved when updating a program. We present two possible approaches; the main intuition behind each of these is to find quiescent points where updates are safe. The first approach requires global synchronisation, and is more generally applicable, but can delay updates indefinitely. The second restricts the class of programs that can be updated, but permits update without global synchronisation, and guarantees application of update. We provide full proofs of all relevant properties