The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables inter-networking, and essentially establishes the Internet.
A point of presence was a location where a long-distance carrier (IXC) could terminate services and provide connections into a local telephone network (LATA). An Internet point of presence is an access point to the Internet.
A Network Access Point (NAP) was a public network exchange facility where Internet service providers (ISP) connected with one another in peering arrangements.
TCP (Transmission Control Protocol) is a standard that defines how to establish and maintain a network conversation via which application programs can exchange data. TCP works with the Internet Protocol (IP), which defines how computers send packets of data to each other. Together, TCP and IP are the basic rules defining the Internet. TCP is defined by the Internet Engineering Task Force (IETF) in the Request for Comment (RFC) standards document number 793.
The File Transfer Protocol (FTP) is a standard network protocol used to transfer computer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and uses separate control and data connections between the client and the server.
An Internet Service Provider (ISP) is a company that provides you with access to the Internet, usually for a fee. The most common ways to connect to an ISP are by using a phone line (dial-up) or broadband connection (cable or DSL).
A computer or program which runs purely to serve the needs of other computers. It runs special that manage communication with the internet.server software to service the requirements of the users (clients). There are several types of servers,including file servers and printer servers on a local area network (LAN), and web and email servers
A computer which uses the services provided by the server.
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Router
A piece of hardware that connects two or more networks. In relation to the internet, data from described as ‘directors of traffic’ for the networks.the ISP is sent into the network and the router then directs the data packets to the correct destinations. The router also handles data travelling in the other direction. Routers can be
ADVANTAGES.Not fixed to astationary computer.Can be used whereverthere is a wireless hubwhich is accessible.DISADVANTAGESNeed to have access to a wireless hub.
Can be less secure than wiredconnections.Tend to have slower data transmissionspeeds than wired broadband methods.
ADVANTAGESBroadbandconnections can givebetter reception andare usually faster thandial-up.DISADVANTAGESRequires a base which is wired in, so it
is less flexible than wireless.
ADVANTAGESCan use existingtelephone circuits,which is useful in some areasDISADVANTAGESOlder technology gives poor receptionat times.The conversion from digital toanalogue signals can cause errors.Tends to be slower than otherconnection methods.
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Hyper-Link
Hyper-link – A link (which can be text or a graphic) which takes you to another web page or location within a document.
Web server – It is the job of a web server to deliver web pages to users’ computers.processes requests via HTTP, the basic network protocol used to distribute information on the World Wide Web. The term can refer either to the entire computer system, an appliance, or specifically to the software that accepts and supervises the HTTP requests.
Web pages are searched for using a uniform resource locator (uRL) , which is a stringof characters that identify a particular web page on the internet. Every web page has aunique URL.URLs are made up of three components.
if you dont know the name of a particular web page or want to find web pages ona particular topic, you can use a search engine to fi nd it. Search engines such asGoogle™ and Yahoo! allow you to enter a description of what you are looking for andthe search engine will search its indexes (databases of web pages) and fi nd matchingitems. The items are normally presented in ranking order, with the most popular orrelevant search result showing at the top of the list.
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codec – A device or programused to encode or decode data.
CODEC
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devices/components –Used as a generic term tomean computers, peripheralhardware, mobile telephones,manufacturing plant,environment monitors and manyother things.
internet packets – A formattedblock of data sent over thenetworks and the internet.A packet contains the addressesof send and destination, the dataand error checking.
Wireless networks are another means by which data can be exchanged between acomputer and a network, including the internet. A wireless network is any networkservicing computers or other devices (e.g. mobile phones), in which the connectionsdo not use cables of any kind. Wireless communication usually uses radio waves, butinfra-red communication is also used.In wireless networking all devices using the network need to have a wireless networkinterface card through which they gain access to the network. The card is used totransmit data across the network and to receive incoming data from the network.Wireless networks have many advantages – probably the most important is mobility;
people are no longer tied to desks and wires.
data – Any kind of informationthat has been formatted in aspecifi c way. Different typesof data include audio, video,images and monitoring signals,as well as text.
Mbps – Stands for megabits persecond. Approximately a millionbits can be transmitted throughthe media in one second.
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Gbps – Stands for gigabitsper second. Approximately athousand million bits can betransmitted through the media inone second.
GBPS
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Sun spot activity – From time totime there is the equivalent ofa huge wave of flame releasedfrom the surface of the Sun.This releases millions of chargedparticles, some of which hitthe Earth. These can causedisruption to data transmissions
Sun spot activity
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Geostationary satellite –A satellite orbiting the Earth at aheight of 35,786 km does so atthe same speed that the Earthis rotating. It therefore appearsto be stationary above a singlepoint on the Earth’s surface.
Geostationary satellite
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next Wednesday page 20- 21- 24-25
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Byte
Byte – In computing andtelecommunications, a byte isunit of digital information whichcommonly consists of eight bits.(See page 19 for a defi nition ofbits.)
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half duplex
Half-duplex transmission: allows two-way transmissions but the devices don’t transmitat the same time. A system being used to monitor and control manufacturing processescan use half-duplex transmissions. It will send a message to the control computer,which will respond with new settings, but they both cannot send messages at thesame time. Some network systems use half-duplex to maximise bandwidth.
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Full duplex transmission: allows two-way communication at the same time.The telephone system, land or mobile, is an example of a full duplex system.
full duplex
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1 Simplex transmission: sends data in one direction only. A radio broadcast is a goodexample of simplex transmission
simple transmission
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paralell transmssion
In parallel transmission, a number of bits of data are transmitted simultaneously overan equal number of wires/channels. This allows the bits in a whole byte of informationto be transmitted together. It has a short range, with an absolute maximum of around5 metres.Parallel transmission used to be popular for connecting printers to computers but it israrely used these days in computing because of its cost and limited range.
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serial transmission, bits are transmitted one at a time over a single wire/channel.This reduces the cost of the cable, but gives a slower rate of data transfer. There is alsosome additional complexity, as bytes have to be disassembled into individual bits fortransmission and then reassembled after receipt. Serial transmissions can be used overlarge distances.] U niversal
This reduces the cost of the cable, but gives a slower rate of data transfer. There is alsosome additional complexity, as bytes have to be disassembled into individual bits fortransmission and then reassembled after receipt. Serial transmissions can be used overlarge distances.] U niversal
serial transmission
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universal serial bus (uSB) is a serial transmission method which was introduced tomake many of the connections to a computer look the same. Nowadays USB is used ina wide variety of devices, such as mobile telephones, memory sticks and MP3 players.USB ports also supply power to some devices.The maximum theoretical transmission rate for USB 2.0 is 480 Mbps, but this is sharedamong all devices on a USB hub, so the rate for each device will be less than this.
Bi-directional transmission has several meanings within data communication, but itis essentially about transmitting in both directions. Most recently the term has beenapplied to fi bre optics. Using the current technology, light passes in one directiononly, so you have to add extra fi bres to the bundle to carry a signal in the oppositedirection.
Bi-directional transmission
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client-side processing is the use of a scripting language to create code on web pageswhich provides interactivity. The important point is that the interaction takes placewithin the web page and the code is downloaded to the user’s computer when theweb page is opened by the user’s browser.A good example of a client-side interaction is a roll over (often called a mouseover),where some code is triggered when you move the mouse over a particular part ofthe web page. This might be something simple like the display of an advertisement,or it could be a demand for some data entry (e.g. fi lling in your details on a socialnetworking website).Benefits of client-side processing include:• Speed: The interaction may be faster once the code has been downloaded with thepage.• Security: It is more secure (than server-side processing) as all the action takes placein the downloaded page and nothing comes from the browser, which could causecorruption or security problems.Disadvantages of client-side processing include:• It is browser specific: Not all scripts work the same way on all browsers, so you mayhave to create different versions depending on the browsers used.• Computer speed: It can be affected by the speed of your own computer. Asall of the activity is taking place on a downloaded web page, the speed of thedownload and the speed of processing will depend on your computer system. If theprocessing is complex or resource hungry, it may run slowly or cause other programsto run slowly on your system.
client-side processing
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] Bi-directional transmissionBi-directional transmission has several meanings within data communication, but itis essentially about transmitting in both directions. Most recently the term has beenapplied to fi bre optics. Using the current technology, light passes in one directiononly, so you have to add extra fi bres to the bundle to carry a signal in the oppositedirection.
Bi-directional transmission
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this can be my break slide tbh
Q: What was the name of the hair salon next to the graveyard?A: Curl Up and Dye.
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DataBase
A database is a system for managing a collection of data. Data about a particular typeof thing – for example, customers or products – is stored in a table . You can think of atable as a grid. Every row in the table holds information about a single item; this is alsocalled a record . Every column holds information about a property of the items in thetable, such as a customer’s name or an item’s price – these properties are called fields
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Table
table – A two-dimensionalrepresentation of data in adatabase.
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Record
Record – A group of selecteddata which are associated insome way.
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Field
Field – A single piece of datawithin a record.
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Primary Key
Primary key – A single uniquekey used to identify each recordin a table.
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Foreign Key
Foreign key – A field which canbe used to cross-reference andaccess associated informationacross many tables.
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DBMS
The DBMS allows you to create, maintain, search and sort data on a database. It allowsdifferent users to access the database at the same time, and can provide differentlevels of access to the data.
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SQL
Structured Query Language (SQL) is a high-level language which is used to undertakethis management activity. It is normally in two parts:1 data defi nition Language (ddL): This is the part which is used to defi ne thedatabase structure.2 data Manipulation Language (dML): This is the part used to add, delete, changeand query the data which is held in the database structure.SQL is the language that generates the code used by the DBMS
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opportunist
opportunist threats. People who fi nd an unattended computer which has beenleft logged in to a system may view, steal or damage information, programs or evenhardware
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virus
computer viruses. These are small programs which can replicate themselves andspread from computer to computer. They are never benefi cial; usually they will makesome changes to the system they infect and, even if they do no real damage, theyare undesirable. They arrive by attaching themselves to fi les or email messages.
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other malware. Examples of malware include: computer worms (essentially acomputer virus which does not need to attach itself to a fi le or message); Trojanhorses, which appear as some benign program allowing a hacker full access to asystem; spyware; adware; and various other nasties. Malware is never benefi cial.
malware
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trojan
Trojans are malicious programs that perform actions that have not been authorised by the user. These actions can include:
Deleting data
Blocking data
Modifying data
Copying data
Disrupting the performance of computers or computer networks
Unlike computer viruses and worms, Trojans are not able to self-replicate.
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Phishing
this type of threat which attempts to gain access to passwords,financial details and other such privileged information. Often this is done by emailmessages pretending to come from trusted websites, instant messaging or socialnetworks. Normally they try to divert you to a website which looks original and which asks for information.
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accidental damage
this may be caused by a natural disaster (e.g. flooding),mischief or accidental mishap, and can result in losing all of a computer’s data.
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physical barriers
Physical barriers. These include turning off computers and locking offi ces when thesystems are unattended to prevent damage by people, the environment (e.g. fi re,fl ooding, electrical interference) or theft.
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password controlling
Password control of access. Passwords are sequences of characters, known onlyto the computer user, which allow access to a computer, network or application.Passwords should always be strong so that it is hard for someone else to guess themor work them out.
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Access levels. These can be set up to allow individuals to have access to onlyspecifi c levels of an application and to prevent unauthorised users from accessingparticular data.
access levels
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Anti virus software
Anti-virus software. This is set up to intercept computer viruses before they canbecome resident on the computer. The software can isolate the virus, remove it andsometimes repair any damage. Equivalent security programs exist for other types ofmalware.
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firewall
Firewall. This is a piece of software that monitors all data arriving at your computerfrom the internet and all data leaving your computer. It stops anything that it thinksis harmful or unwanted (such as viruses, spam, Trojan horses and hackers).
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encryption. This is used to codify data so that it cannot be read by anyone who doesnot have the key to the code. An algorithm, sometimes known as a cipher, is appliedto the data at the transmission end and the reverse is applied at the reception end.
encryption
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Backup and recovery. Making a backup of data is the only way of recovering from atotal data disaster. Many individuals and organisations back up data to Flash ® solidstate storage devices or magnetic tape at night. The tapes are stored safely in aseparate place, so that they are not destroyed by any disaster which could destroythe master system (fi re, earthquake, etc.). Many types of backup exist, including:Full system backup of all data held for a specifi c purpose.Incremental backups of fi les or data that has been changed since the last fullbackup. This is faster than running a full back up every time.Backups to removable media, such as a removable hard drive (if you have a largeamount of data), USB sticks, CDs and DVDs.It is also possible to back up data across a network (or across the internet) to a server ina completely separate location (for example, backing up data to the cloud).
backup and recovery
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data protection act 1998
provides 8 principles that govern the way data about individuals is stored and used.
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introduced to protect from hackers and malicious use of viruses
computer misuse act 1990
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copyright designs and patents act 1998
protects creators of the original piece of work, art, music or pictures.
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freedom of information act 2000
provides individual the right to see information stored about them. data can also be accessed about public bodies.
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The Data Protection Act controls how your personal information is used by organisations, businesses or the government.Everyone responsible for using data has to follow strict rules called ‘data protection principles’. They must make sure the information is:
used fairly and lawfully
used for limited, specifically stated purposes
used in a way that is adequate, relevant and not excessive
accurate
kept for no longer than is absolutely necessary
handled according to people’s data protection rights
kept safe and secure
not transferred outside the European economic a without adequate protection
There is stronger legal protection for more sensitive information, such as:
ethnic background
political opinions
religious beliefs
health
sexual health
criminal records