Hardware components

RAM

stores the computer’s programs and data temporarily while the power is on; random access memory

ROM

stores information like how to run the computer; always there even if you turn the computer off or on; read only memory

Storage Devices

(disk drives, flash drives, CDs) store data permanently even when the power is off

CPU

processes the program’s instructions and performs arithmetic and logic operations; central processing unit

Input

devices (keyboard, mouse) transfer information into the computer’s memory.

Output

devices (console, printer) transfer information out of the memory

Control Unit

• Fetches an instruction 

• Fetches data

• Executes the instruction

• Constantly looking for the next instruction of what to do

• “Supervisor”

ALU

• Performs the “math” and “logic”

• Transforms/transfers information when needed

• Executes the algorithm

• “Employee”

Registers

• Memory locations reserved for what the CPU is currently using; Information constantly being copied back and forth between registers and main memory across a collection of wires 

• The fastest type of data storage or memory you can have

Program Counter

Keeps track of which operation to execute next

CPU levels of abstraction

control unit —> ALU —> Registers —> Processing counter