The computer system has one or more inputs to provide data. This data is then processed in some way. The outcome of the processing is sent to an output or it may be stored until some event happens to cause it to be output. what For processing to take place, there needs to be a set of instructions of needs to be done. This set of instructions is called a program. This system is called a stored-program computer. The very first commercial computer in the entire world of this type was built in Britain in 1949 and was called the Manchester(Ferranti) Mark 1. The beauty of this type of computer system is that it is flexible the machine performs a different task by simply loading a different program from storage.