Computer basics

CPU ( central processing unit)

performs all processing ( the “ brain” of the computer)

CPU’s speed depends on

architecture and clock speed

clock speed is measured in

GHz (GigaHertz)

system unit 

main body of the computer (not including monitor, keyboard, or mouse)

system unit contains

motherboard, CPU, RAM, expansion cards, and power supply 

buses

electrical pathways that transfer data between components 

Expansion cards 

add extra features

expansion card examples

• video card ( graphics display)

• ethernet card (network connection) 

• sound card ( audio processing) 

ports

connection points for external devices (USB, HDMI, Ethernet, etc.)

modem

converts digital data for internet transmission ( and vice versa)

Input devices

devices that send data to the computer (keyboard, mouse, scanner, webcam)

Output devices

devices that display or send out information

impact printers

physically strike paper ( e.g. dot matrix)

non impact printers

no contact (e.g. Inkjet, laser)

LCD monitor ( Liquid Crystal Display)

flat, light, energy efficient

CRT monitor ( Cathode Ray Tube)

bulky, older technology

Moores law

predicts that the number of transitors on a microchip doubles every 18-24 months

super computer

extremely powerful, used for scientific research and stimulations

main frame

large scale computers for corporations (process millions of transactions)

servers

provide data/services to other computers

embedded computers

built into other devices ( cars, appliances, etc.)

generations of computers

each shows advances in speed, size, cost, reliability, and ease of use 

generation 1

vacuum tubes 

generation 2

transitiors 

generation 3

integrated circuits

generation 4

mircroprocessors

generation 5

AI and quantitative computing

Bit

smallest unit of data (0 or 1)

Byte

8 bits =1 byte

1 KB =

1,024 bytes

1 MB=

1,024 KB

1 GB=

1,024 MB

1 TB

1,024 GB

machine language

binary code understood by computers

BPS

bits per second ( speed of data transfer)

Uploading

sending data to the internet

downloading

receiving data from the internet

four major computer functions

input, processing, output, and storage

input

entering data (keyboard, mouse)

processing

CPU executes instructions

output

displaying or sending results

storage

saving data for later use

Primary storage

ram ( cache memory), temporary (volatile), fast, smaller capacity, active when computer is on

secondary storage 

hard drive ( SSD, flash drive, CD/DVD), permanent (non-volatile) slower, larger in capacity, and data remains after shutdown

two types of software

system and application

system software 

runs the computer 

application software

helps user perform tasks ( Microsoft, excel, photoshop)

upgrading software

installing newer versions for improvement or security

freeware

completely free of use

shareware

“try before you buy”

software suite

bundled applications ( e.g. Ms office)

GUI ( Graphic user interface)

allows users to interact visually supports WIMP- windows, icons, menus, pointing devices 

Operating Systems (OS)

windows 10/11,macOS, linux, unix, DOS

booting

starting the computer

ROM BIOS

firmware that helps initialize hardware when booting

OS functions

processor management, memory management, file management, device/ peripheral management, security, and multitasking 

utility programs

supports and maintains the system:

• anti-virus software

• add remove programs 

• file compression (ZIP) 

• system resotre and backup 

• task scheduler

User Interface

part of the OS that facilitates your interaction with the computer and the programs you use