Random access memory= programs being used are held

ROM=Read only memory=programs stored here tell needed.

binary digits=bits

bits are either 0 or 1

Kilobyte=____ bytes

abbreviated "k"

Megabyte=_____ kb

MB

Gigabyte=____ MB

GB

Terabyte=_____ GB

TB

32 bit less capable and cheaper

64 bit=can address more main memory

provides some service to multiple users

pixel=single point in a graphic image

dot pitch=measures distance between pixels

pixel pitch=measurement of smallest bit of data in an image.

1.operating system software-controls computer resources

2.Application program software-helps users accomplish tasks

1.windows

2. mac os

3.Unix

4.Linux

horizontal provides capabilities common across all organizations or industries.

Vertical= software serves need of a specific industry

Thin=only require a browser

Thick=requires software programs including the browser

pros=free, often just as good as paid versions, freedom to do what you want

cons=often no customer service, may not do exactly what you want/need

File based and Data Based.

Disadvantages: data redundancy, limited data sharing, lengthy development times

Advantages:DATA based approach gets rid of problems

Primary Key=column that identifies a unique row in a table.

Foreign Key=columns that fulfill a row

Fkey needed because sometimes that key is a primary key of a different table in which it resides

databases that carry their data in the form of tables and that represent relationships using foreign keys.

2 Tables that are directly related ex. student # and table of activities that have the student #s that are participating

1.potential update loss

2.potential locking problems

3.possible data conflicts

A data model is similar to blueprints for a house. It’s a logical representation of database data that describes data and their relationships

Entity relationship data model-tool for constructing data models 

Developers use it for describing the content of a data model by defining the entities that will be stored in the database and the relationship between those entities

Entity-some thing that users want to track

Identifier-an attribute whose value is associated with one and only one entity instance.

Relationships between entities.

Maximum-max # of entities involved in relationship

Minimum-Constraints on minimum requirements

One to many: 1:M

Many to Many: N:M

Normalization:process of converting poorly structured table into two or more well structured tables.

You normalize to preserve data integrity.

3 types of networks

LAN-local area network

MAN-metropolitan area network

WAN-Wide area network-networks of networks

NIC-network interface card

MAC-media access control

UTP-unshielded twisted pair cord 

Fibre optic cable

protocol is a set of rules that two communicating devices follow

switch is a special purpose computer that recieves and transmits messages on the LAN

NIC-network interface card-connect circuitry to LAN cable

WNIC-wireless network interface card

MAC-media access control-address unique identifier

most popular ethernet-IEEE 802.3 protocol. cord

Wireless protocol-IEEE 802.11-wireless

Alternatives for WAN and Wimax

WAN-Sprint and Verizon use EVDO, ATT and Tmobile use HSDPA

Wimax- 4G

Access point-connect each site to the transmission device

Protocols-standardized means for coordinating activities between two or more entities

Frame Relay, ATM, their protocols and PSDN

(Public switch Data Network)-WAN alternative

frame relay-type of psdn that processes traffic in the range of 56 kbps to 40 mbps. Slower and easier to support

ATM-Asynchronous transfer mode-process speeds from 1 to 156 mbps. some organizations need ATMs speed

ISP-Internet service provider.

3 functions

1.provide users with legit internet access

2.Serve as a gateway for users to connect to internet

3.Help pay for internet by collecting fees from users

1.Dialup modem- uses telephone line. super slow, uses PPP proticol-point to point

2.DSL modem-uses telephone line but faster.

-Assemetric-different upload/downloadspeeds

-Symmetric-same download speeds

doesnt slow if 100 users using

3.Cable modem-tv line excess of 256 kbps. can slow down with many users

modem-converts digital signal to analog.

Router-special purpose computer that moves network traffic from one node to another

Digital subscriber line

Asymmetric digital subscriber line-different upload and download speeds

Symmetrical digital subscriber line-same upload and download speed

Public switched data network-network of computers and leased lines that is developed and maintained by a vendor that leases time to other organizations.

Virtual Private Network-uses internet to create appearance of private point to point connections. encrypts data and more costly. but more secure!

Criteria for comparing wide area networks

WAN

Need 2 firewalls for protect 

perimeter outside firewall

and internal firewall

encryption is the process of transforming clear text into coded unintelligible text for secure storage or communication

Asymmetric encryption-different keys are used. one key for encoding and the other key decodes.

HTTPS is the most secure protocol used today

http isnt nearly as secure

Secure Socket Layer and Transport Layer Security combine public/private key with symmetric encryption to protect you 

hypertext transfer protocol

Simple mail transfer protocol-email protocol

File transfer protocol-application layer protocol

physical address of where the device is-never changes

IP address are logical numerical addresses which can change.

Network address translation-process of changing private IP address' into public ones

Architecture- an arrangement of protocol layers in which each layer is given specific tasks to accomplish

Protocol-Each layer of the archetecture, there are one or more protocols, each protocol is a set of rules that accomplishes the tasks assigned to its layer

Program-A program is a specific computer product that implements a protocol

Every computer has an address. You then connect to a server which takes you to the router. After the router you get on the internet where you can find your friends URL and go there to his router and IP address.

uniform resource locator-documents address on web

Public-used on internet assigned to major institutions

Private-used within private networks and internets. they are controlled only by the company that operates the private network or internet

Process of changing a domain name into its IP address (Layer 5 application

ICANN-Internet corporation for assigned names and numbers

IPTV-internet protocol television-broadband connection needed. allows you to send and recieve video messages.

VoIP-Voice over IP- allows you to send voice conversations

both use TCP-IP-OSI technology