1.3 INFORMATION PROCESSING CYCLE

input is any data or instructions that we enter into the computer system for processing. There are some common ways of feeding input data into the system, which are: typing on a keyboard and pointing with a mouse.

The processing unit controls all activities within the system. For every instructions, the control unit repeats a set  of four basic operations called the machine cycle(fetch, decode, execute and store


Function of CPU

1. Fetch a program instructions or data item from memory
2. Decode the program instructions into signals that computer can execute.
3. Execute the instructions.
4. Store (return) the result of instructions to the memory
5. Interprets and carries out basic instructions that operate a computer
6. Control unit direct and coordinates operations in computer
7. Arithmetic logic unit(ALU) performs arithmetic, comparison, and logical operations

The central processing unit consist of two part: the control unit (CU) and the arithmetic logic unit (ALU). Each part has specified functions. The control unit tells us rest of the computer system how to carry out a program's instructions. It directs the movement of electronic signals between memory, which temporarily holds data, instructions and processed information, and the arithmetic-logic unit. It also directs these controls signals between the CPU and input and output devices.

Arithmetic-logic unit performs two types of operations: arithmetic and logical. Arithmetic operations are fundamental math operations: addition, subtraction, multiplication, division. Logical operations consist of comparison.

The storage is a location in which data, instructions, and information are saved for future used. Every computer uses storage to hold system software and application software. There are two types of storage, which are primary storage and secondary storage.

Output is data that has been processed into a useful form, called information. There are four types of output, which are texts , graphics, audio and video.