System model where many processors can be simultaneously executing different instructions on different data. Furthermore, these processors operate in a largely autonomous manner as if they are separate computers. They have no central controller, and they typically do not operate in lock-step fashion. Most real world banks run this way. Tellers do not consult with one another, nor do they perform each step of every transaction at the same time. Instead, they work on their own, until a data access conflict occurs. Processing of transactions occurs without concern for timing or customer order. But customers A and B must be explicitly prevented from simultaneously accessing the joint AB account balance. MIMD relies on synchronisation mechanisms called locks to coordinate access to shared resources. See also mutual exclusion, mutex lock, semaphore lock, single-lock strategy, spin lock.