haihongyuan.com
海量文库 文档专家
全站搜索:
您现在的位置:首页 > 幼儿教育 > 少儿英语少儿英语

1-Looking at Computers Understanding the Parts

发布时间:2014-02-12 12:00:12  

Technology in Action
Chapter 1 Looking at Computers: Understanding the Parts

1

Chapter Topics
? ? ? ? ? ? ? Functions of a computer Data versus information Bits and bytes Input devices Output devices System unit Ergonomics
2

Computers Are Data Processing Devices
? Computer’s four major functions:
– Gathers data (users input data) – Processes data into information – Outputs data or information – Stores data and information

3

Data vs. Information
? Data: Representation of a fact or idea ? Information: Organized, meaningful data

4

Bits and Bytes: The Language of Computers
? Bit
– Binary digit - 0 or 1

? Byte
– Eight bits

? Each letter, number, and character = a string of eight 0s and 1s

5

How Much Is a Byte?
Name Byte Kilobyte Abbreviation B KB Number of Bytes 1 byte 1,024 bytes (210 bytes) Relative Size Can hold one character of data. Can hold 1,024 characters or about half of a double-spaced typewritten page. Can hold approximately 768 pages of typed text. Approximately 786,432 pages of text; 500 sheets of paper is approximately 2 inches, so this represents a stack of paper 262 feet high. This represents a stack of typewritten pages almost 51 miles high. The stack of pages is now 52,000 miles high, or approximately onefourth the distance from the Earth to the moon. The stack of pages is now 52 million miles high, or just about twice the distance between the Earth and Venus. The stack of pages is now 52 billion miles high, some 20 times the distance between the Earth and Pluto. Megabyte Gigabyte MB GB 1,048,576 bytes (220 bytes) 1,073,741,824 bytes (230 bytes)

Terabyte Petabyte

TB PB

1,099,511,627,776 bytes (240 bytes) 1,125,899,906,842,62 bytes (250 bytes)

Exabyte

EB

1,152,921,504,606,846,976 bytes (260 bytes)

Zettabyte

ZB

1,180,591,620,717,411,303,424 bytes (270 bytes)

6

Types of Computers
? ? ? ? Handheld: Smartphone, Tablet Notebook: Portable PC Desktop: Used at a single location Mainframe: Supports hundreds of users simultaneously ? Supercomputer: Performs complex calculations rapidly – scientific research ? Embedded: Self-contained computer performing dedicated functions

7

Computer Software
? Software: Programs that enable hardware to perform different tasks
– Application software - System software

8

Computer Hardware

9

Input Devices
? Devices used to enter information or instructions into the computer
– Keyboard – Mouse/ pointing device – Microphone – Scanner – Stylus

10

Standard PC Keyboards
? The QWERTY layout is standard on most PCs ? Enhanced keyboard features include number, function, and navigation keys.

11

Specialty Keyboards
? Notebook keyboard ? Tablet or Smartphone onscreen keyboard ? Smartphone flip-out keyboard ? Virtual laser keyboard

12

Mice
? Optical mouse
– Needs no mouse pad – Doesn’t need cleaning

? Trackball
– Easier on wrists – Stays stationary on desk

? Wireless
– Use radio w

aves (Bluetooth)

? Integrated pointing device
– Touchpad – Trackpoint
13

Other Input Devices
? Game controller ? Scanner ? Camera (Webcam, Smartphone, Tablet Cams)

14

Inputting Sound
? Microphones used for:
– Podcasts – Videoconferencing – Internet phone calls – Speech recognition
15

Input Devices for People with Disabilities
? People with visual impairments
– Voice recognition – Keyboards with large keys – Touchscreen keyboards

? People with motor control issues
– Special trackballs – Head-mounted devices

16

Output Devices
? Send processed data out of the computer
– Display Monitors – Printers

? Output devices make:
– Soft copies (video, sounds) – Hard copies (print)

17

Display Types
? CRT Cathode Ray Tube
– Uses much more space – Uses more energy – Legacy technology

? LCD Liquid Crystal Display and LED Light
Emitting Diode
– – – – – – Use far less space Weigh less Brighter More energy efficient Cause less eyestrain Widescreen

18

Key Display Features
? Image quality is measured by:
– Resolution: maximum pixels on the screen – ie 1680 X 1050 (21”), 1280 X 1024 (19”)
– Screen size: inches between diagonal corners of screen – ie 19”,21”,22”, 23”,26” + – Dot pitch (s): distance between pixels – Color depth: number of colors a monitor and graphics card can display – Contrast ratio – the ratio of the brightness of the color white vs. the brightness of the color black - higher is better
19

Other Video Output
? Touch-screen devices
– Double as both input and output devices

? Data projectors
– Project a computer image to a large screen for sharing with large groups

? Virtual Reality ? Augmented Reality

20

Printers
? Impact printers
– Dot-matrix

? Nonimpact printers
– Inkjet – Laser

? Specialty printers
– Multifunction – Plotter – Thermal

21

Nonimpact Printers
? Inkjet
– Less expensive device – Print high-quality color images cost effectively

? Laser
– More expensive device – Faster printing speed – Less expensive per page in B&W – Color lasers are becoming less expensive

22

Choosing a Printer
? ? ? ? ? ? Speed (ppm) Resolution (dpi) Color output Memory Cost of printer Cost of consumables

23

Outputting Sound
? Speakers and headphones

24

The System Unit
? Box that contains the central electronic components of the computer:
– CPU/RAM/ motherboard – Expansion cards – Power supply – Storage devices

25

Hard Disk Drive
? Permanent (nonvolatile) storage ? Internal or external versions

26

Optical Storage
? Compact discs (CDs) ? Digital video discs (DVDs) ? Blu-ray discs (BDs)

27

Flash Drives/Flash Memory
? Flash drives (jump drives)
– Newer storage alternative – Plug into USB ports

X
28

? Flash memory cards
– Slide into slots in the system

Storage Media Capabilities

Solid State Drive

2 – 6 TB – External vs. Externa

l Portable vs. Internal

Up to 256 Gb

29

Inside the System Unit
? Essential electronic components used to process data ? Types of components:
– – – – – Power supply Hard disk drive Motherboard CPU Expansion cards
30

The Motherboard
? CPU ? RAM ? Expansion cards and slots ? Built-in components

31

Central Processing Unit (CPU)
? ? ? ? Referred to as the “brain” of the computer Controls all functions of the computer Processes all commands and instructions Can perform billions of tasks per second

32

CPU Performance Measures
? Speed
– Megahertz (MHz) – Gigahertz (GHz)

? Cores
– Single – Dual – Quad

33

RAM vs. ROM
? Random access memory (RAM):
– Stores instructions and data – Temporary (volatile) storage – Transient: contents constantly changing

? Read-only memory (ROM):
– Stores start-up instructions – Permanent storage

34

Expansion Cards
? Add functions ? Provide new connections for peripheral devices ? Common types:
– Sound – Video (VGA) – Network (NIC)

35

Types of Ports
? ? ? ? ? USB HDMI Audio FireWire USB Hub ? Connectivity
– Ethernet – Modem

36

Power Controls
? Power-on button: Turns on system; should not be used to turn it off ? Other options:
– Sleep mode – stored in RAM – Hibernate – stored on hard disk – Warm boot

37

Setting It All Up: Ergonomics
? Ergonomics: minimizing injury or discomfort while using the computer ? Steps to follow:
– Position display correctly – Use adjustable chair – Assume proper position while typing – Take breaks – Ensure adequate lighting
38


网站首页网站地图 站长统计
All rights reserved Powered by 海文库
copyright ©right 2010-2011。
文档资料库内容来自网络,如有侵犯请联系客服。zhit326@126.com