Computer System

About

A computer is a device of device controlled by a special device called a CPU.

It consists then of:

at least a processor (CPU),
a memory device where:
- primary storage holds data only temporarily, at the time the computer is executing a program.
- secondary storage holds permanent data
and input/output interfaces (also device). (Ex: Input: mouse, keyboard, joystick - Ouptut: a monitor, television)

This invention of the transistor started the whole computer industry as it permits automatic switching of electric signal.

Hardware is a specific physical implementation of a logical computer represented by an Instruction Set Architecture (ISA) and an organization.

Code (Machine code) in a computer are called instructions.

All computer operations are carried out by a device and are built from the combinations of logic gates (ie the combinations of boolean functions). Se Instruction - Cycle

The function is built at hardware level.

Example:

A lot of function can be programmed without modifying its hardware.