Computer Essentials
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What Is a Computer?
What is it?
What are its parts?
What can I do with it?
How can I buy one?
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A programmable device that can:
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Accept information (input)
Process information ((change)
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Give out information (output)
Store information(save for later use)
Programmable – it can be given a set
of instructions (called a program)
which it stores for later use.
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Parts of a Computer
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Input Devices
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Hardware — the physical parts of the computer:
„ Input devices
„ Processor
P
„ Output devices
„ Memory
„ Storage devices
System Unit – main “box” that holds the
motherboard (with processor and memory)
Input Devices – the parts of the
computer that accept information.
Examples include:
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Keyboard
Pointing Device — mouse, stylus (pen)
Touch screen part of a monitor.
Sound inputs (microphone, audio jack)
Video inputs (video jack, digital camera)
Scanner (creates an image of a document)
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Processor
(Microprocessor)
Output Devices
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Output Devices – the parts of the
computer that give out information.
Examples include:
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Processor - the “thinking” part of the
computer – also called the CPU (central
processing unit). Consists of:
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Display Devices (monitor) – CRT or flat
panel
Printer – dot matrix, ink jet, laser
Audio jacks
Video jacks
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Control Unit — interprets instructions and
directs the flow of information inside the
computer
Arithmetic/Logic Unit — performs operations
on the data
„ Arithmetic (addition and other mathematical
operations)
„ Logic (compares two bits of data)
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Memory Types
Memory Size
RAM — Random Access memory
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Changes as you use computer applications
Temporary (gone when you power down)
ROM — Read Only Memory
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Permanent (for the most part)
Used at power-up time (“boot”) to give
computer information needed to get started
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Bit — single switch capable of being on or off
Byte — bank of 8 switches working together —
y For example,
p , each byte
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the basic unit of memory.
can hold a character (letter, digit, etc.)
Kilobyte — (Kb) approx. 1,000 bytes
Megabyte (Mb) — ~1,000,000 (million) bytes
Gigabyte (Gb) — ~1,000,000,000 (billion) bytes
Terabyte (Tb) — ~1,000,000,000,000 (trillion)
bytes
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Storage
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Types of Information
Diskette (Floppy Disk) — holds 1.44 Mb
Zip Disk — holds 100-250 Mb
CD-ROM — typically 650 MB
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Software – information consisting of the program
(set of instructions) used by the computer
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CD-ROM — pre-written with permanent data
CD-R (recordable) — blank, can record data once
CD-RW (rewritable) — blank, can write, erase, re-write data
many times
DVD (digital video disk) — 4.7 to 17 GB
Hard Disk Drive — typically 100 Gb – 1000 Gb (1 Tb)
Flash Memory Cards & Flash Drives (“miniature
media”) — generally 1 to 16 Gb
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Types
„ System software — controls the operation of the
computer
„ Application software — programs that allow the user
to perform specific useful tasks
Data – The information that gets processed by the
software.
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Doucuments, Numbers, Images, Sound, Video, etc.
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Application Software
(Examples)
System Software
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The most important system software is the
Operating System:
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Loads when you turn on the computer (“booting”)
Controls input and output
Interprets the application program instructions
Handles “housekeeping” chores
Windows is “GUI” operating system — Graphical
User Interface
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Uses visual icons (symbols) and a mouse
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Word Processing — create documents
Spreadsheet — calculations on rows & columns of data
Database — organize, sort and retrieve similar types of
data
Presentation — create slide shows
Desktop Publishing — like word processing but more
powerful manipulation of text and images in a document
Graphics — create and edit images
Multimedia — integrate text, sound, video and still
images
Utilities – help you manage your computer more easily
(e.g., virus protection software)
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Networking
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The Internet
Network — a group of computers
connected by communications hardware
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The world’s largest network, delivering text,
graphics, audio, video, etc. It includes:
LAN (Local Area Network) — connects
computers within a building or a group of
nearby buildings
WAN (Wide Area Network) — connects
computers over a larger geographical area
Internet — The world’s largest network,
connecting hundreds of millions of users
worldwide
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World Wide Web — huge collection of
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documents
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E-mail and Instant Messaging — messaging
among users
Newsgroups — shared information on specific
topics
File Transfer Protocol (FTP) — ability to transfer
files from one computer to another worldwide
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The Internet
The World Wide Web
What You Need
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Computer — preferably with multimedia capabilities
Connection hardware — phone modem, network
card, cable or DSL modem, etc.
Communications software – Windows has built-in
built in
software. AOL provides its own.
Browser software — provides a user-friendly interface
to view web pages — Internet Explorer, Firefox, etc.
ISP — Internet service provider — with whom you
connect:
„ Commercial provider
„ School or employer may provide service
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A collection of billions of documents
(web pages) organized on web sites
g the internet.
connected through
These pages have hyperlinks —
instant connections to other web pages
worldwide.
There is an almost limitless variety of
information on the web.
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Web Pages
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E-mail
Each page has a unique URL — uniform
resource locator:
http://www.cheyney.edu/calendar.htm
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http:// — hypertext transfer protocol (consists of
rules for reading the data)
www.cheyney.edu — domain name (the unique
name of web site on the web server computer)
calendar.htm — the name of the web page file on
the computer
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E-mail address – consists of a unique user
name and domain name: [email protected]
With email, you can:
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Set up an address book with your often-used
addresses.
Set up your own distribution lists of users to
facilitate bulk mailings.
Send files as attachments to your messages,
including images and video
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Chat
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E-Commerce
Chat – real-time communication:
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Type chat — users communicate by typing
messages and reading them as they are
typed
Voice chat — using a microphone and
speaker
Video chat — using a microphone and minicamera
Internet phone — connect to regular phones
(land lines and cell phones)
Electronic Commerce – online business:
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You can purchase goods and services in
many ways — direct sales, auctions, banking,
stock
t k trading,
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etc.
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You should use a secure browser that
encrypts your credit card number into code
that makes it unreadable during transmission
Use caution when giving out personal
information.
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Internet Threats
and Defense
Internet Research
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Like all research, you must consider the
reliability of the source.
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Search Sites: Yahoo, Google, Bing, etc.
Educational: universities, museums, libraries,
research institutions, etc.
Media & Entertainment: magazines, music,
newspapers, radio, tv, film, sports, etc.
Government (National, State, Local): agencies,
statistics, services, taxes, tourism
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Viruses — programs (often harmful) that replicate themselves and
spread to other computers — Use anti-virus software and keep it
updated.
Spyware — programs that track your actions and examine your
computer — Use anti-spyware software.
Illegal Access to your computer — Use firewall software.
Identity Theft — unauthorized use of your personal information,
usually used to steal from you — Never give out passwords or
personal information on an unknown or insecure site.
Bogus Sites (“phishing”) — look exactly like a real site in order to
steal your private information — Never give out personal data at a
URL that has been e-mailed to you.
Adware — Generates ads (more of nuisance than threat).
Spam — bulk email – Spam filters are a somewhat helpful.
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Purchasing a Computer
Purchasing a Computer
Shopping Tips
Considerations & Recommendations
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Type: desktop or laptop?
Windows or Mac? Consider purpose and compatibility.
Memory & Speed – 3 Gb RAM, 1.6 GHz speed minimum.
Storage – 200 Gb hard drive minimum
DVD Drive – Get a burner
Printer – color ink jet or black laser?
Communications – wireless network card
Bundled software – word processor
Avoid the bare minimum features — plan for future
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Buy a major brand
Check vendor’s reputation — a slight price
increase may be worth using a more reliable
vendor
Be aware of extra costs — disks, paper, furniture,
Internet provider fees, etc.
Check return policy for conditions and fees
Consider a service contract
Use a credit card
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