operation

An operation, in mathematics and computer science, is an action that is carried out to accomplish a given task. There are five basic types of computer operations: Inputting, processing, outputting, storing, and controlling.

Although even basic computers are capable of sophisticated processing, processors themselves are only capable of performing simple mathematical operations. CPUs perform very complex tasks by executing billions of individual operations per second.

When we think of computer operations, we’re usually thinking of those involved in processing. The arithmetic-logic unit (ALU) in the processor performs arithmetic and logic operations on the operands according to instructions that specify each step that must be taken to make the software do something. 

The arithmetic operations are addition, subtraction, multiplication, and division.  There are sixteen possible logic (or symbolic) operators used to perform tasks such as comparing two operands and detecting where bits don’t match. Boolean operators, which work with true/false values, include AND, OR, NOT (or AND NOT) and NEAR. Relational operators, used for comparisons, include the equal sign (=), the less-than symbol (<) and the greater-than symbol (>).

The ALU usually has direct input and output access to the processor controller, main memory RAM and input/output devices. Inputs and outputs flow through the system bus. The input consists of an instruction word that contains an operation code, one or more operands and sometimes a format code.