Short Review about Computer Science

1969, US department of defense, was originally text only. 1990's media became available

an access device (computer with a modem), means of connection (phone line, internet hook up, etc), and and internet service provider

Expressed how much data can be sent through a communications channel in a given amount of time

Slow type of signal that only allows for one signal to be transmitted at a time

high-speed connections

downloading information from local to remote computer

downloading data from remote to local computer

low speed but inexpensive modem, ie.

phone lines or dial up

can be either internal or external

expensive, is always on, high speed, less than 4.5 miles from phone company to work

very expensive, generally used by large organizations.

TV cable system with internet connection, company usually supplies a cable modem, is always on, 100 mbps

transmits data between satellite dish and satellite orbiting the earth, connection is always on,

wireless fidelity, transmits data wirelessly for up to 54 mbps

internet service provider, local regional or national organization that provides access to the internet for free

WISP, Sprint, AT, verison, etc. enables wireless-equipped laptops and tablets and smartphone users to access internet

One huge network that connects a lot of smaller networks

Computer requesting data or services

/Host computer is the central computer that gives out information upon request

a collection of modems and other equipment in a local area, local gateway access to ISP network

a routing computer at the point on the internet where several connections come together, run by private companies, allows different ISP's to change internet traffic

high-speed and high-capacity data transmission lines usually fiber optic, uses the newest technology (sprint, AT&T verison etc.)

cooperative University/business education and research project, takes old lines and adds new "toll lanes" to internet to speed things up

connecting to your ISP's POP, handshaking: fastest speed of transmission established, authentication: User ID and password

the set of rules a computer follows to electronically transmit data

fixed length blocks of data transmission; transmissions are broken up into packets and reassembled at destination

Internet Protocol address: unique address that connects devices to the internet

Address changes each time with use, versus not changing at all

web is multimedia based and the internet is what supports the web

protocol (https://), domain name (barnsandnoble.com), directory name/file path (/sellback), file name and extension (home.

htm)

yahoo, google, bing, ie a gateway website

compile their own searchable data bases on the web

allow you to search information by selecting a list of categories or topics

allows you to search several site engines at once

helps locate specialized subject matter such as info on movies or health or jobs (think WebMD)

a piece of software that can be downloaded and used to make a website for free that can be corrected or added to by anyone

Do-it-yourself labels that people can put on anything foundon the Internet, from articles to photos to videos, that help themto find their favorite sites again and to link them

Computers; communicating with 1 and 0s

humans operate in an analog, uses wave variation. sound light and temperature are analog

they convert analog data into digital data that computers can then use

WAN; communications network that covers a large geographical area (long distance phone calls)

MAN; used to communicate in a city or suburb (cellphone users)

LAN; connects computers or devices to one another in a close range of each other (ie one office space or building). The organization that has the LAN owns it. (home area network)

request data

supply data

all computers on the network are equal and communicate directly with one another with out needing a server

functions as internet but for one company to use and access internally

similar to intranets but used by external sources (such as suppliers)

use a public network (usually the Internet)plus intranets and extranets to connect an organization's various sites) buton a private basis, via encryption and authentication

any device attached to the network

all nodes are connected through a central network switch

all nodes are connected into a continuous loop

All nodes are connected to a single wire or cable

A bus or network of star networks

message sent to the destination can take any shorted, easiest route to teach its destination

used for dial up connections; two strands of insulated copper wire twisted around eachother (slow

insulated copper wire wrapped in a metal shield, used for cable TV and cable internet services

transmits pulses of light, not electricity, lower error rate, more expensive, more durable, very fast

radiation is the basis of all telecommunications signals, wired and wireless

part of the electromagnetic spectrum that carries most communications signals

used for regular telephone communication

Geo- earth orbitMeo- medium earth orbitLeo - low earth orbit

program that hides in a file program or disk that cause unexpected effects

program that repeatedly copies itself onto the computer

bad programs that disguise themselves to be useful to infultrate computer information

allows access to personal information, such as the study of keystrokes

gives access to remotely control computer

automatically adjusts settings for you

uses a reflecting mirror to reflect incomping light into crisper photos