In computing, booting is the process of starting a computer as initiated via hardware such as a button on the computer or by a software command. After it is switched on, a computer's central processing unit (CPU) has no software in its main memory, so some process must load software into memory before it can be executed. This may be done by hardware or firmware in the CPU, or by a separate processor in the computer system.
Switches and cables used to program ENIAC (1946)
Initial program load punched card for the IBM 1130 (1965)
IBM System/3 console from the 1970s. Program load selector switch is lower left; Program load switch is lower right.
PDP-8/E front panel showing the switches used to load the bootstrap program
Computer hardware includes the physical parts of a computer, such as the central processing unit (CPU), random access memory (RAM), motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices such as a monitor, mouse, keyboard, and speakers.
PDP-11 CPU board
Inside a custom-built computer: power supply at the bottom has its own cooling fan
Computer motherboard
An IBM System z9 mainframe