Flashcards
Learning aim B flashcards
Flashcards do conjunto (93)
- 1Server. A server is a computer, a device or a program that is dedicated to managing network resources.Runs special software to serve others computers ; different types include file, print, web and email servers.
- 2Client.A computer/ device that uses services provide by a server; the computer you use to access the Internet is a client.
- 3Router.Devices that route (direct) data traffic through a network; they are intelligent and will try to find the best routers.
- 4Backbone.A 'big' cable (often fibre optic) that connects a large number of devices in the 'core' of the Internet.
- 5Network diagram.
- 6Pop (Point of Presence).It is an access point to the Internet.
A point of presence is an artificial demarcation point or interface point between communicating entities.
An ISP may have several Pops to allow good access to the Internet. - 7NAP ( Network Access Point).It is where different networks interconnect, such as your home network onto the Internet.
- 8Network diagram.
- 9ISP ( Internet Service Provider).It is the industry term for the company that is able to provide you with access to the Internet, typically from a computer. If you hear someone talking about the Internet and they mention their "provider," they're usually talking about their ISP.
- 10Dial up connections. It is a wired connection via modem & phone wires.Advantages:
- can use existing telephone wires, gives connection where broadband is not available.
Disadvantages:
older technology and can give poor reception, usually slower than other methods, conversation between digital and analogue can cause errors. - 11Broadband. Means a wired connection via a broadband supplier.The advantage of broadband is the fact that has better reception and speed than dial-up.
The disadvantages of broadband are:
wired, so has to be used on a stationary computer, broadband is not available in many rural areas. - 12Wireless. Connects without using cables.Advantages:
not fixed to a stationary computer, can be used whenever wireless Internet is available ( eg wi-fi hotspot).
Disadvantages:
Needs to have a wireless Internet available, can be less secure than wired, tend to be slower than wired. - 13Bandwidth.Is how we measure the speed of the Internet connection.
Bandwidth is how much capacity/ space there is to carry digital data as 1s and 0s.
Measured in bits per second.
High bandwidth means more data can be moved, so giving a faster Internet connection and a higher transmission. rate. - 14Bandwidth picture.
- 15HTTP means HyperText Transfer Protocol.HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands.
- 16Protocol.Protocols are rules that allow computer system to connect with different system to transfer data.
This is important because the Internet involves many different types of devices. - 17HTTPS means Hypertext Transfer Protocol Secure.Hypertext Transfer Protocol Secure is an extension of the Hypertext Transfer Protocol (HTTP).
It is used for secure communication over a computer network, and is widely used on the Internet. - 18FTP means File Transfer Protocol.Protocol which allows the files to be transferred between two computers or devices.
It is usually used to upload or download files to a server. - 19TCP means Transmission Control Protocol.It is a standard that defines how to establish and maintain a network conversation via which application programs can exchange data.
TCP is responsible for breaking data into packets and assembling the packets when they arrive. - 20IP means Internet Protocol.The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying data grams across network boundaries.
Internet Protocol is responsible for handling the routing of packets, that's addressing, sending and receiving packets over the Net. - 21Hyperlinks. It is a link from a hypertext document to another location, activated by clicking on a highlighted word or image.The web works because of hyperlinks.
They connect web pages together.
When a hyperlink is clicked, a user is taken to another page on the site, or taken to another website. - 22Browsers.Web pages are accessed through browsers.
These are application which allows a user to enter a URL and view a webpage.
Your browser reads the HTML code and display the page. - 23A web image.
- 24Web servers.Websites are stored on web servers.
When you access a website through a browser, the page is temporarily downloaded onto your computer.
It is the web server's jobs to deliver the web page requested. - 25URL mean Uniform Resource Locator.A URL is an address for a webpage
and is used to specify addresses on the World Wide Web.
A URL is the fundamental network identification for any resource connected to the web (e.g., hypertext pages, images, and sound files). - 26Protocol.The protocol specifies how information from the link is transferred. The protocol used for web resources is HyperText Transfer Protocol (HTTP).
The protocol tells the browser what to do with the URL. - 27Domain name.The domain name is the computer on which the resource is located. It is the name of the website.
- 28Path.This points to a specific webpage.
- 29URL image. Uniform Resource Locator.
- 30Search Engine diagram. Search engines are special websites that allow users to find data on the internet.
- 31Web spiders/Web crawlers.To collect details of websites, the search engine use automated programs
(or 'bots') called web spiders or web crawlers. - 32How search engines work.1. A user enter keywords into the search engine.
2. The search engine searches its index, which is its database of web pages.
3. The results are displayed in ordered of popularity. - 33How search engines work.4. Don't forget that the 'sponsored links' will also be placed at the top.
5. The more a company pays, the more likely it is to appear in search results. - 34The index.They look around the web, looking for for new or updated pages and log them in the search engine’s database called the index.
- 35Smart searching with operators.Use quotes- search for an exact word or a set of words.
Use minus- exclude all results that contain a certain word.
Use star- find all variations of a word
(called a wildcard).
Use OR- find one keyword or another use the term OR (in capitals). - 36Client ans server side.Client-side refers to operations that are performed by the client in a client–server relationship in a computer network.
When functions, procedures, calculations or other processing are performed on a server, they are considered server-side. - 37Store and forward.Emails are stored on servers & then forwarded to the receiver - so it's called 'store & forward'.
Emails are sent from an sender's Outbox and received in a recipient's Inbox.
The sender & recipient do not have to be online at the same time. - 38Store and forward.That's great when sending emails to people in different global time zones.
This appliers to staff in a big company, as well as families & friends. - 39Advantages of using email.Attachments- you can attach multiple files, such as images or documents.
Copy- use CC to send copy to other people or use BCC to hide addresses from others.
Contacts- 'Address Books' store contacts & you can also use distribution list to em,ail lots of people simultaneously. - 40Address book.An address book is a database that stores names, addresses and other contact information for a computer user. Address books allow easy access to the user's friends, family, business associates and others by maintaining their email and other contact details on their computer.
- 41Contact group.A contact group is a set of email addresses that you can use to send an email message or meeting invitation to everyone at once. To create a contact group, see Create a contact group.
- 42CC (Carbon Copy).Short for carbon copy or courtesy copy, CC is a copy of an e-mail to be shared but requires no reply or action. For example, it is not uncommon for an employee who is sending an important message to other employees to also CC their manager or boss to help keep them up-to-date.
- 43BCC ( Blind Carbon Copy).Bcc stands for blind carbon copy which is similar to that of Cc except that the Email address of the recipients specified in this field do not appear in the received message header and the recipients in the To or Cc fields will not know that a copy sent to these address.
- 44Advantages of using email.Delivery speed- emails usually arrive in seconds - much faster than traditional post.
Web-mail- gmail & Hotmail use cloud servers so can access email anywhere. - 45Disadvantages of using email.Junk email - Spam
Spam or 'junk' email has become a massive problem.
Phishing- fake emails designed to trick people to give personal details.
Viruses (from attachments)- attachments can contain code designed to harm your computer. - 46Disadvantages of using email.Delayed reply- email isn't real time so you can't expect and instant response.
No access- not everyone has email or they might not logon regularly. - 47Diagram.
- 48SMTP means Simple Mail Transfer Protocol.SMTP handles sending.
It pushes outgoing email to a server.
If ever a problem sending, them SMTP will keep trying until it's sent. - 49IMAP means Internet Message Access Protocol.IMAP handles receiving webmail.
Let you access your email on server.
When logon, you pull email from server.
So you can access 'anytime, anywhere'. - 50POP3 means Post Office Protocol 3.POP3 also receiving messages.
POP originally came webmail when people used 'email client software' eg MS Outlook.
You download emails form server.
Then emails could be deleted from the server. - 51Webmail.Not everyone uses webmail services such as Gmail & Hotmail.
All your messages stay on the server:
+ Can access email on many devices.
+ Email backed-up.
- You must have Net connection.
- Slow service. - 52Email client. Some people use software applications called' email clients'.Emails download to client machine:
+ Can access them, even if not online.
+ Client software has more features.
- Emails lost if computer crashes. - 53Data Packet diagram.
- 54Packet switching.Packet switching is the process of data being broken into 'packets' before being sent through a network and then re-assembled at the other end.
- 55Advantages of packet switching.Packets chose different routes so traffic flow is efficient.
Big files can still be sent but don't clog network.
Packets give security benefit because if intercepted, the hacker will only have one part of a file. - 56Disadvantages of packet switching.If one or more packets are lost or corrupted during transmission, the whole file will not be received correctly.
Requires Large amount RAM (Random Access Memory) to handle large amount of data communication in packets. - 57What are codecs?A codec is a device or computer program for encoding or decoding a digital data stream or signal. A coder encodes a data stream or a signal for transmission or storage, possibly in encrypted form, and the decoder function reverses the encoding for playback or editing.
- 58Simplex.Simplex - One way.
Signals go on in one direction at same time.
Example:
Remove control to television. - 59Half duplex - Two way.Signals go in both directions but not simultaneous.
Example:
Radious. - 60Duplex - Take turns.Signals go in both directions at same time.
Example:
Mobile phones. - 61Serial and parallel transmission.Two ways of transmitting digital data as a steam of bits.
Bits of data are transferred one at a time over a wire. - Serial.
Bits of data are transferred simultaneously - a whole byte can be transferred at the same time. - Parallel. - 62Benefits and limitations.Good over large distances. - Serial.
Faster because more bytes transferred per second. - Parallel.
Limitations:
Complex because data has be broken into individual bits. - Serial.
Only for shorter distances (eg 5 meters) - Parallel. - 63Unshielded and Shielded Twisted Pair, Co-axial, Fibre optic.UTP/STP - contains pairs of copper wires twisted together, used for LANs (Large Area Network).
Co-axial- Is solid cooper wire with thick shielding, used to connect TV with aerial.
Fibre optic - strands of glass carry data as light. Used for backbone of network. - 64Infrared.Uses infrared light to transmit data.
That's very high frequency light.
Benefits - The infrared is reliable.
Drawbacks - short range, devices must be in line of sight.
Can suffer from interference. - 65Microwave.Uses waves with short wavelengths to transmit data.
Advantages - Good for medium distances.
Disadvantages - can suffer from interference from other devices eg a microwave oven that's near to a computer device. - 66Satellite.Uses satellites in space to relay data between points on earth eg GPS.
Advantages - good for very long distances.
Disadvantages - very expensive. - 67UTP/STP benefits and drawbacks.Benefits - cheaper than other methods, reliable,
- under plastic coating, the shielded (STP) has protective layer around the copper wires to protect data signal from interference.
Drawbacks - slow, low capacity, used over short distances, susceptible to interference, which means data can be interfered with if near another digital device. - 68Co-axial advantahes and disadvantages.Advantages - It is reliable.
Disadvantages - Slow, low capacity, used over short distances, thick and physically inflexible, susceptible to noise. - 69Fibre optic benefits and drawbacks.Benefits - fast, used over long distances. little interference.
Drawbacks - used for backbone of network. - 70NIC & NAP. Network Interface Card & Network Access Point.Devices using wireless networking need a NIC.
Network Interface Card it's the hardware for receiving wireless signals.
It's built-into modern devices eg tablets & phones.
The NIC connect to a NAP.
Network Access Point.
Lots of places offer NAPs, such as cafes & libraries. - 71Client side processing and Client scripts.Client side is viewing webpages on your
client device.
Today's webpages have lots of features that are interactive.
Interactivity is achieved using Client Scripts written in a language called JavaScript.
These client scripts are run by your browser to display the interactive effect. - 72Client side processing examples.Hover image - on same webpages, images change when you move your mouse pointer over them.
This 'hover' effect and is achieved using code in a client script. - 73Client side processing examples.Slider - Another common interactive feature on websites is a 'slider' where you click or swipe to scroll through images.
This is creating using code in a client script. - 74Client side advantages.Speed - Processing is faster on the the client because data does not have to travel back to the server across the Internet.
Security - Data cannot be intercepted on the client in the same it can be when data is transmitted back to the server across the Internet. - 75Client side disadvantages.Browser-specific - Different browsers process client scripts in different ways, therefore a web develop cannot be sure how their website will appear on a screen on the client side.
Computer speed - The web developer is relying on the speed of the client computer to deliver the interactive features, so if that is slow then the processing will be slow. - 76Server side processing.Server side means processing data at the 'back end' on the web server.
That's all the nerdy work that ordinary people never think about!
It's done using special server scripts written in server - side languages such as PHP.
All this usually happens after you've done something on a webpage. - 77Server side processing examples.Submitting a web form - After you click SUBMIT your data is sent back to the web server for processing, such as storing your personal details on website's database.
- 78Server side processing examples.Submitting a web search - After you click search your keywords are send back to the web server for processing, such as finding matches on the database or Index. Then the results are send back to you.
- 79Server side processing benefits.Server are powerful computers - a web server is likely to be way more powerful than a client computer, so it can process data faster.
No browser involved - server don't use Browsers so there are none of the difficulties you get on the client with different brands.
Efficient - everything is done on the server, so no need to wait for download etc. - 80Server side drawbacks.Security - when data is send back from the client, it has to travel across the Internet where there is ore risk of security threats.
Overloading - if a lot of users are asking the web-server to process data, it could overload the server and cause it to crash( when thousands of people try to book big tickets.) - 81Database, Table, Field, Record and Primary Key.A database is a structured collection of data.
A table stores a set of data e.g. details of all the students in school.
A field are the columns in a table e.g. forename, surname, gender, date of birth.
A record is one row that stores data about a single item e.g. a student's details.
The primary key is a special field with a unique identifier e.g. a student ID. - 82Foreign Key.The foreign key its purpose is to link to the supplier table.
- 83Relationship.Most databases need more than one table to store all the data.
So the tablets need to be linked to create a relational database. - 84Data types: Text, numeric, Date/Time, Boolean.Text - Any kind of characters, including letters & numbers.
Numeric - Numerical value.
Date/Time - Dates and times.
Boolean - one of two values, such as Yes/No or True/False. - 85Database diagram.
- 86Local & Online databases.Local means a database held inside a network to keep it secure.
Online means a database that could be accessed around the world. - 87One feature of an online and local database.Shops such as Argos plus search engines & social networks all use databases.
The database is stored server-side.
And the data is sent with the webpage when you load it. - 88DBMS. Database Management System.A DMBS is software that allow you to create & use your own database.
It creates tables and fields and allows you to search and sort data.
It handles security to prevent un-authorized access.
It can also allow for different levels of access for different users. - 89SQL. Structured Query Language.SQL is the language used by a DBMS to actually create & search a database.
It has a Data Definition Language (DDL) to set-up the tables.
And it has a Data Manipulation Language ( DML) for updated & search queries. - 90HTML tags. HTML is the language used to create webpages. "Hypertext" refers to the hyperlinks that an HTML page may containThe tag defines a paragraph.
The HTML tag is used to create a 'b' element, which represents bold text in an HTML document. - 91The tag defines a part of text in an alternate voice or mood.The tag defines an image in an HTML page.
The tag defines a hyperlink, which is used to link from one page to another. The most important attribute of the element is the href attribute, which indicates the link's destination. - 92The tag tells the browser that this is an HTML document.When writing in HTML, the tag is a block element used to designate an unordered list.
The HTML tag defines the main content of the HTML document or the section of the HTML document that will be directly visible on your web page. - 93The tag tells the browser that this is an HTML document.the tag in HTML, will usually be the title of a post, or other emphasized text on the page.
defines a list.
Informações
- Descrição
- FlashCards sobre Learning aim B flashcards, criado por Andreaa-Bianca Teohar em 04-11-2019.
- Criado por
- Andreaa-Bianca Teohar · nov 2019
- Atualizado
- 4 dez 2019
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