Number Systems in Computer Science

Binary, Decimal, and Digital Information

MIS 2201 • Lecture Notes

Lecture Sections

Introduction: Why Do Computers Use Different Number Systems?

Computer Components Overview

Computers consist of four main components:

Input Devices

Keyboard, mouse, camera, microphone

Output Devices

Monitor, speakers, printers

Processor (CPU)

The “brain” that performs calculations

Memory

RAM (temporary) and Hard drives (permanent)

The Electronic Reality

Due to the electronic design of computers, all data must be represented using:

  • ON state: +5 Voltage (represented as 1)
  • OFF state: 0 Voltage (represented as 0)

This is why computers use Binary Numbers (only 0s and 1s) internally, even though humans prefer Decimal Numbers (0-9).