A computer architecture conceived by mathematician John von Neumann, which forms the core of nearly every computer system in use today (regardless of size).In contrast to a Turing machine, a von Neumann machine has a random-access memory (RAM) which means that each successive operation can read or write any memory location, independent of the location accessed by the previous operation.A von Neumann machine also has a central processing unit (CPU) with one or more registers that hold data that are being operated on.The CPU has a set of built-in operations (its instruction set) that is far richer than with the Turing machine, e.g. adding two binaryintegers, or branching to another part of a program if the binary integer in some register is equal to zero (conditional branch).The CPU can interpret the contents of memory either as instructions or as data according to the {fetch-execute cycle}.Von Neumann considered parallel computers but recognized the problems of construction and hence settled for a sequential system.For this reason, parallel computers are sometimes referred to as non-von Neumann architectures.A von Neumann machine can compute the same class of functions as a universal Turing machine.[Reference?Was von Neumann' s design, unlike Turing' s, originally intended for physical implementation?].(2003-05-16)