1. Computer Concepts Lesson 2
Computer Technology

2. Output Devices Return (to you) processed data in form of information
View and use information

3. Types of Output Devices
Monitor
Printer
Speakers
Earphones
Printed copy = hard copy = held in your hand
Computer Monitor = soft copy = not something you can physically hold
Audio = soft copy
NOTE: some devices, like a monitor, can be input and output: e.g., Applebee’s screens = touch-screen

4. Pixel
Pixel – picture element, a single point in a graphic image

5. Monitor Clarity Resolution Sharpness of image Pixels per square inch
800 x 600 = large display
1280 x 1024 = small display
Types: cathode ray tube (CRT); flat-panel display (LCD) – uses liquid crystal; consumes less space and less than 1/3 power of CRT
Size: diagonally 14” 15” 19” 21”; COST (can be part of package or sold individually up to $6,000
Resolution: sharpness/clarity of image; more pixels per square inch the better (pixel is smallest unit on the screen that can be turned on or off or made to appear in different shades). Some programs require certain resolutions (RAM determines resolution).
Columns and rows: 640x 480 = 307,200 (less clear and sharp)
800x600; 1280 x 1024 up to 1600 x 1200 (the more pixels there are per square inch, the better the resolution)
Dot Pitch=amount of space between pixels; the closer dots, the crisper the image
.28 dot pitch = dots are 28/100ths of millimeter apart
Less than .31 provides clear screen
.25 standard (better) for desktop publishing
Refresh rate=# of times per second that pixels are recharged for bright glow onscreen
Phosphors hold glow for fraction of section; higher refresh rate the better
Should be at least 72 Hz (hertz)

6. Printers Dot Matrix - impact Inkjet Laser – black and white or color
Plotter
Impact = dot-matrix, dying out, mechanism like typewriter strikes against ribbon
Draft quality (coarse) or near-letter quality
Slow
Laser=images created by series of dots
Images created on a drum (like a photocopier)
Magnetically-charged ink (toner) powder)
Sharp, clear images
300 to 1200 dpi (dots per inch)
Quiet
Fast (4-32 pages per minute)
Cost higher: $ dpi
$1700-$5000 for color laser
Ink-Jet==dots; spray electrically charged droplets of ink from four nozzles through holes in matrix; high speed
Less expensive $150-$500, depending on quality and color
Slower than laser (1-4 pages per minute)
Less resolution ( max)
Plotter=specialized device to produce high-quality graphics in colors; large items such as maps, architectural drawings.

7. Printer Comparison Printer Type Output Speed Quality Cost
Characteristics
Laser
Fast
Best
Most Expensive
Ink-Jet
Medium
Good
Affordable
Dot Matrix
Slowest
Not as good
Varies
Ink Jet – up to 1200 x 4800 dpi

8. Laser Printers - Operation
Prints series of dots created on a drum (like a copy machine)
Uses toner – magnetically charged ink
Produces highest-quality printouts
Black or Color
A workhorse—for those who print a lot

9. Inkjet Printer - Operation
Squirts liquid ink on page.
Prints on a variety of media
Good for invitations, flyers, brochures, photos
Slower than laser printers
Photo printers, all-in-one’s

10. Dot Matrix Printers - Operation
Prints by striking mechanism against ribbon, similar to typewriter.
Draft or NLQ (near letter quality)
Creates inexpensive drafts (not good for final documents)
Produces lower resolution than laser or ink- jet.
9-pin
24-pin

11. Communications and Networks
Media that connects networked computers
Wired – telephone lines or cable
Wireless – microwaves, satellites, and radio waves
Transmission speed:
28.8 Kbps 10 seconds
56 Kbps 5 seconds

12. Internet Connectivity
Dial-up – 56 Kbps
DSL – 128 Kbps Mbps
T1 – 1.5 Mbps
T3 – 44.6 Mbps
Fiber Optic – 5 Mbps – 50 Gbps
Leased from telephone company (copper or fiber optic)

13. Fiber Optics
Transmitting information from one place to another by sending pulses of light through an optical fiber.

14. Networks and the Internet
Network – connected computers and devices
LAN – local area network
Share printers and files
WAN – wide area network
Network Interface Card – NIC
Connectivity hardware placed in expansion slot. The blinking light on the outside of your computer tells you the NIC is active and has network connectivity.
Internet – world’s largest network

15. Software

16. Types of Software Operating Software Application Software
Tells computer how to operate
Application Software
Programs that perform specific tasks

17. Operating System Software
Purpose
The purpose of an operating system is to organize and control hardware and software so that the device it lives in behaves in a flexible but predictable way.
Examples
Microsoft Windows 8, 7, XP
Mac OS
Unix
Linux
XP Home can be installed over Windows 98 and ME
XP Professional can be installed over 98, Me, NT 4.0, and Home
XP Professional includes corporate security, advanced group policy settings, roaming user profiles, etc.

18. Application Software Categories
Word Processing
Spreadsheets
Database Management
Communications
Personal Finance/Accounting
Graphics
Desktop Publishing
Computer-aided Design
Antivirus
Web Design
Communications software gives you the following capabilities, among others:
*Online connections
*Use of financial services – e-commerce, stock market, home banking
*Remote access connections via modem
*File transfer
*Fax

19. Multitasking is . . .
the apparent simultaneous performance of two or more tasks/programs by a computer's central processing unit

20. Icons
Small picture or graphic object that represents a program , file, command or web page
Most computers functions in a GUI (graphical user interface) are represented by a function icon.
The icon must be original, distinctive, and tiny.

21. GUI
Pronounced: gooey
A type of user interface that allows users to interact with programs in more ways than typing
A GUI offers graphical icons, and visual indicators, as opposed to text-based interfaces, typed command labels or text.
The actions are usually performed with
Touch
Mouse

22. DOS (Disk Operating System)
Command line operating system
What Mrs. Brunson grew up with (at the time it was so cool because we didn’t know any better)
Still used for advanced networking and disk management functions