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Computer Systems Test 2

STUDY
PLAY
Internet .VS. WWW
The internet is a network of networks. Where as the WWW is a way in which we use these networks to access information.
Inventor of the Internet
Tim Berners Lee
e Commerce
Business to Consumer, Business to Business, Consumer to Consumer. The use of the Internet for financial transactions.
Cookies
A bit of data that allows businesses to track your preferences on the internet. Often help decide which ads to be sent.
Mal ware
Malicious Software- Software designed to infiltrate a computer without the consent of the owner.
Hyperlink
a reference to a document that the reader can directly follow, or that is followed automatically
2 inventions leading to internet boom
Hypertext and Web Browsers
URL
a Uniform Resource Locator (URL) is a subset of the Uniform Resource Identifier (URI) that specifies where an identified resource is available and the mechanism for retrieving it.
Client VS Server
A client is a consumer or individual a server is the company supplying the connection to the internet
Communications Protocol
a set of rules that ensures the orderly and accurate transmission and reception of data
TCP IP
The Internet Protocol Suite (commonly known as TCP/IP) is the set of communications protocols used for the Internet and other similar networks.
HTTP
HyperText Transfer Protocol are the rules computers use to transfer web pages across the Internet.
IP Address
a number that uniquely identifies each computer or device connected to the Internet
Slowest connection to the internet
Dial Up
What is an Internet service provider
A company that provides a connection to the internet
Previous Internet Name
DARPA NET
Hypertext
a way of formatting pages with embedded links that connect documents to one another, and that also link pages to other objects such as sound, video, or animation
HTML
Language of the websites
Virus
A program that attaches itself to another program and spreads itself to other computers. Viruses are hidden within the code of a host program
Worm
A virus that spreads through a network from node to node
Intellectual Property Rights
concept that says that a particular group may determine how indigenous knowledge and its products may be used and distributed and the level of compensation required
Identity Theft
the co-option of another person's personal information (e.g., name, social security number, credit card number, passport) without that person's knowledge and the fraudulent use of such knowledge
Networking
-Computer network:Two or more computers connected together
-Devices connected to networks: nodes
-Benefits of a network: Sharing resources, Transferring files
Peer to Peer Network
-Network where a few computers share hardware and information & All computers are equal, and each can have access to devices and files on the others
-Each computer independently stores its own software and information, but can access the information on the other computers
-All computers can access devices connected to any of the other computers
-Used mainly at home & small offices
Client Server Network
-A network in which one or more computers are servers and provide services to the other computers, which are called clients
-Servers have hardware, software, and/or information that the client computers can access
-Servers are usually powerful computers with large storage systems
LAN
Local Area Networks- Nodes are within a small geographic region: Homes, Schools, Small businesses
WAN
Wide Area Networks- LANs connected over long distances: A few miles to thousands of miles using telecommunications lines
Network Interface
a card or software that enables a laptop computer to send and receive data over a network.
Hub
Connects computers in a network
SIMPLEST form of connecting computers.
Switch
-Receive retransmit data to nodes on the same network
-Sends messages only to the computer that is the intended recipient
-Can handle multiple communications channels at the same time
-Can temporarily segment parts of the network with high traffic from the rest of the network
Router
-Connects computers into a network, and also connects dissimilar networks together
-Can handle multiple communications channels
Cabling VS Wireless
Cat 5, Twisted Pair VS Radio waves, WiFi and Bluetooth
Wifi
a local area network that uses high frequency radio signals to transmit and receive data over distances of a few hundred feet
Protocol for Wireless Communication
-Uses radio waves to connect nodes
-Basically an Ethernet network that uses radio waves instead of wires
Each node requires a wireless network adapter: Transceivers
Bluetooth
a proprietary open wireless protocol for exchanging data over short distances (using short length radio waves) from fixed and mobile devices, creating personal area networks (PANs).
Hacker
-Anyone who unlawfully accesses a computer system
-Types of hackers:
White-hat
Black-hat
Script kiddies
Virus Prevention
Anti-Virus Software, Firewalls must update so that new viruses do not infiltrate
Database
Multiple tables related together
Field
a single piece of information to be stored about an entity
Key Field
A field that contains a unique value for each value, that is used to I.D. an entity
Foreign Key
Key used to create relationships between the tables.
Record
Multiple fields about one entity
Compound Table
A table with multiple keys and entity's
Process to create Database
Create proper structure and definitions, -What entities do you want to store information about, -What fields do you want to store about those entities, - I.D. the Key field, -Normalize, -Establish relationships between the tables
Normalization
The process to structure tables in order to prevent data redundancy and inaccuracies
Data Types
Text, Number, Date, Time, Currency, Boolean (Yes/No, True/False)
Diff. Table Relations
1-1, 1-Many, Many-Many (if many-many occurs you create another table to make them 1-many)
ERD
Entity Relationship Diagram- illustrates the relationships between the tables.
Referential Integrity
A set of rules to maintain consistency between related tables
Query
A question asked about data stored with in a database
SQL & QBE
Structured Query Language & Query By Example- QBE builds the SQL
Select Statement
A query/statement that: selects or extracts data
Update Statement
A query/statement that: updates data
Insert Statement
A query/statement that: inserts data
Delete Statement
A query/statement that: deletes data