This section looks at the inner workings of computers, the processor, the memory, logic gates and the transfer of data and signals throughout the computer.
A LITTLE HISTORY
In the 1940s a stored program concept was pioneered by physicist John Von Neumann following on from some of the theoretical concepts conceptualised by Alan Turing and much earlier Ada Lovelace. Prior to this early computers were built do a specific task and any changes to this task would require hardware adjustment. In the late 1940s a computer called 'The Manchester Baby' was built, and is now widely recognised as the first proof of concept stored program computer.
Whilst there are now many different types of computer CPU architecture the basic principles of the Von Neumann architecture provide a good understanding of how the CPU works.
The stored program concept is a fundamental idea in computer architecture that describes the ability to store both instructions and data in the same memory space. In the Von Neumann CPU model, the stored program concept is used to enable the computer to execute programs that are stored in memory.
The Von Neumann architecture is based on the concept of a central processing unit (CPU) that can execute a sequence of instructions stored in memory. The CPU has an instruction register (IR), a program counter (PC), and a memory unit. The CPU fetches an instruction from memory using the program counter, which is then stored in the instruction register for decoding and execution.
The stored program concept allows the computer to execute programs that are stored in memory by treating instructions as data. This means that instructions can be loaded into memory just like any other data, and then executed by the CPU. The instructions are organized into a program that the CPU can follow to execute a specific task.
In the Von Neumann model, the instructions and data are stored in the same memory space. This means that the CPU can read both instructions and data from the memory unit. The program counter keeps track of the memory address of the next instruction to be executed, and the CPU fetches and executes instructions in sequence.
The stored program concept enables the computer to perform a wide variety of tasks by executing different programs stored in memory. It also allows for the flexibility to modify or replace programs without having to physically rewire the computer's hardware. This makes the Von Neumann architecture a versatile and widely used model for modern computers.