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ComputerSystems

A computer is . . . A purely digital device

Definition: Digital is a type of electronic signal that is processed, sent and stored in bits—binary digits

Computers use binary coding—a coding system that uses two numbers--1 & 0

In computer terms, the bit is the smallest unit of measurement a computer can understand

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Bits to bytes . . . 8 bits equal 1 byte

A byte is a single character of data, such as a letter, number, etc.

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Term Abbreviation

Approximate Size

Kilobyte KB or K =1000 bytes (actual size is 1024 bytes)Megabyte

MB =1 million bytes

Gigabyte

GB =1 billion bytes

Terabyte

TB =1 trillion bytes

A computer is device that . . . Uses stored instructions

(programs) Accepts data that user supplies

(input) Manipulates data according to a

program (processing) Stores data (storage) Produces results (output)4

What types of data . . . ?

Text data – letters, numbers, and special characters

Graphic data – photographs, charts, and drawings

Audio data – voice and music Video data – moving pictures

and images5

Computer systems The physical components of a

computer system are called hardware. Hardware typically includes:

System unit, monitor, keyboard, mouse Peripheral devices (extra) such as a

printer or scanner

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Computer system vs. System unit Computer system—the

system unit along with input and output devices

System unit—the part of a computer system that processes data and stores information

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Embedded Smartphone Handheld Tablet Netbook Laptop

Desktop All-in-One

Server Mainframe Super Wearable

Computer systems

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Handheld

Smartphone

Netbook

Tablet

All-in-one

Supercomputer

Wearable

Server

Embedded Vehicle

Laptop

Mainframe

System unit

The main circuit board of a computer is the motherboard.

The central processing unit is located on the motherboard. The CPU is the circuitry that processes information—the “brain” of the computer.

The speed of the processor is controlled by the system clock.

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System clock

Controls the timing of ALL computer operations; measured in hertz—one cycle per second. Speed is measured in gigahertz (GHz)—a billion cycles per second. It takes about one-tenth of a second to blink

your eye; a computer can perform some operations 10 million times in the time it takes you to blink you eye.

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The most popular brand processors on the

market are AMD and Intel.

Main memory Main memory is located on

the motherboard. It is also known as primary memory: Random Access Memory (RAM)

Temporary memory available to the user; typically measured in gigabytes

Read Only Memory (ROM) Permanent memory that handles basic startup

functions, known as BIOS—basic input/output systems

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Input Devices: Any hardware component that allows

a user to enter information into a computer Keyboard Pointing Devices Scanners Multimedia

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Keyboards

Solar Ergonomic-Split

Flexible

Blue-Tooth / iPad

Ergonomic-Split

Child’s Toddler Wireless

Gaming

Virtual

Virtual

LED-Color Changing

Pointing devices: Mouse Trackball Touch pad—typically found on

laptops

Pen input—pen-like device touches surface of screen to digitally input data

Touch screen—touching the screen with your finger digitally inputs data

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Scanners Bar code reader—reads

universal product codes (UPC) Optical mark reader (OMR)—

reads “bubble” sheets marked with pencil

Optical character reader (OCR)-reads handwritten or typed text

Page scanner—digitally captures an image or text

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Multimedia Microphone Electronic music keyboard Video camera Digital camera Virtual reality devices

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Output device Any hardware component that can

convey information to the user Display devices (soft copy: data projected

on a screen) Printers (hard copy: data printed on

paper) Speakers

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Display devices360°

Pico Projector HDTV

Flat-Screen MonitorProjector

Interactive Whiteboard

DocumentProjector

Printers The two most common types of printers

are ink-jet and laser The speed of a printer is measured by

the number of pages per minute (PPM) that can be printed

The quality of a printer is measured bythe number of dots per inch (dpi) thatcan be printed

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Storage devices The media on which data and

information are kept Three classifications:

Magnetic—hard disk Optical—CD, DVD, Blu-ray

Information is burned on the disk by laser Flash—memory cards, flash drive

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Communication devices Devices that make it

possible for a user to communicate with another computer Most popular: modem

Phone, cable, DSL Computers on a network use

network interface cards (NIC) Wired or wireless

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KB MB GB TB CPU PPM NIC

DPI RAM ROM UPC OMR OCR

Abbreviations

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Mbps Hz GHz HDTV USB PC