Computer as an Electronic Machine

Computer is defined in the Oxford dictionary as-

"An automatic electronic apparatus for making calculations or controlling operations that are expressible in numerical or logical terms".

The basic function performed by a computer is the execution of a program. A program is a sequence of instructions, which operates on data to perform certain tasks. In modern digital computers data is represented in binary form by using two symbols 0 and 1, which are called binary digits or bits.

Computer Organization and Architecture:

In very basic sence, Computer organization refers to the composition of computers with all necessary components and peripherals. All components connected together and working like a PC is what we call Computer Organization. On the other hand, Computer architecture refers to the way these components communicate together. The modes of communication, mutual synchronization, error handling and all related activities are under the scope of Computer Architecture.

The Von Neumann Architecture:

A computer is a machine that accepts data, processes the data according to the instructions provided by the user, and finally returns the results to the user and usually consists of input, output, storage, arithmetic, logic, and control units.

Most of today's computer designs are based on concepts developed by John Von Neumann referred to as the Von Neumann architecture. Von Neumann proposed that there should be a unit performing arithmetic and logical operation on the data. This unit is termed as Arithmetic Logic (ALU). The Arithmetic Logic Unit (ALU) and the Control Unit (CU) together are termed as the Central Processing Unit (CPU). The CPU generates addresses for searching data or instructions from the memory. Later it performs certain actions on these data or instructions.

Consider the following diagram: