CompSci Final Exam Notes.docx

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Computer Science
Computer Science 1033A/B
Vivi Tryphonopolous

CompSci Final Exam Notes Lecture 2: Introduction/Beginning Multimedia  text, images, animation, sound, video - Before someone judges you? Janet Elsea says you have 7-15 seconds to make a good impression - Multimedia and communications is to make an impression on the Internet! - Communication  effectively communicate a message – clear, exact, professional, make an impression - Five senses are mechanisms to communicate with others and environment  most important sense is sight (view images) then touch, followed by sound (voice recordings, music) then touch (navigate) - “Using a combination of moving and still pictures, sound, music and words, especially in computers or entertainment” – Cambridge definition of multimedia - How do we communicate?  Directly speaking to people, telephone, text messaging, radio, television, World Wide Web - The World Wide Web Offers (1) Accessibility – reaches to people all over the world (2) Is fast (3) Directly see people (i.e. webcam, Skype) (4) Is cheap - The WWW is the voice of power – which area has more people? Asia. Which area has the most Internet users? North American (78.3%). Which area has the least Internet users? Asia and Africa History of Multimedia - 15,000 – 13,000 BC  prehistoric humans paint images on the walls of their caves - 1878  first motion picture ever recorded (The Horse in Motion) - 1914  silent movies incorporated multiple media by using film and text caption together - 1927  first full length movie, The Jazz Singer, with synchronized dialogue (i.e. the first talkie) - 1928  Walt Disney debuts the second short starring a Steamboat Willie, Mickey, and is the first cartoon to use synchronized sound - 1928-1931  Movies with sound replicate silent movies - 1930s  Technicolor is introduced in film and most movies are filmed in colour after 1940 (The Wizard of Oz filmed in Technicolor in 1939) - 1937  Bell Laboratories had a breakthrough in creating dual sound tracks on film. Fantasia was the first commercial movie with a complete surround sound soundtrack in 1940 - 1969  NETWORK TECHNOLOGY INTRODUCES ARPANET (Advanced Research Projects Agency Network)  starts in 1962, first packet switching network and the predecessor to the internet (1) Objective: build a network technology to allow researchers at various locations across the country to share information (2) 4 locations (1969) – UCLA, Stanford, Santa Barbra, University of Utah - 1971  First email sent - 1977  Apple starts to build and dominate the personal computer market - 1981  IBM PC announced/introduced and captures market share in 18 months - 1991  World Wide Web debuted by Tim Berners-Lee - 1992  MS Windows 3.1 - 1992  HTML (language in which webpages are based on) - 1993  the first graphical browser is born (allows us to see web pages containing IMAGES), it is called Mosaic, by Marc Andreessen, Erin Brina, and Tim Clark - 1994  The Rolling Stones become the first major band to broadcast a live performance over the internet - 1995  Disney releases Toy Story, the first feature length computer generated movie - 1996  Affordable digital cameras widely available - 1998  Google Search Engine operates by Larry Page and Sergey Brin - 1999  Napster debuts, allowing users to download and share MP3s - 2000s  Integration of computer, memory storage, digital data camcorders, MP3 players, IPods, speakers, telephones, HD TV and other technologies explodes! - 2001  Apple introduces iTunes and the iPod - 2005  launches - 2007  Search engine giant Google surpasses Microsoft as "the most valuable global brand," and also is the most visited Web site  Faces of the Internet Legacy – Bill Gates (Microsoft Team), Larry Page and Sergey Brin (Google), Tim Berns-Lee (responsible for World Wide Web), Marc Andreessen, Erin Brina, and Tim Clark (Mosaic)  Progression of Technology: 1981 – PC, 1991 – WWW, 1992 – Windows, 1993 – Mosaic (browser), Google (search engine)  Legal Issues:  Copyright, rights, management, privacy, intellectual property  Problematic because of the rapid change in technology  Is it necessary to have the web design skills set? Absolutely! We are moving towards a paperless society  Articulate, think, and write clearly - for report, documentation  Web design skills an essential – Power of the Internet!  Every career requires multimedia skills – IT and design Text - Text can be used to serve two purposes (1) Convey information (2) Visual impact (posters, websites, etc.) - What can you do if you really want to use an unusual font on your website?  Create a .jpg or .gif file of the text in Photoshop so it can be read by all – than insert it into your website - Text sets a mood How is text used? - Colour - Colour is defined by: Hexadecimal Code – always made up of decimals (0-9) and letters (A-F) - Represents RRGGBB (ex: red= FF0000, green= 00FF00, blue= 0000FF) - Western Purple = #660099 - Font type – Arial, Times New Roman, Comic Sans - Style – regular, bold, italic, superscript, subscript - Kerning – adjusting the space between pairs of letters (cha r a cter) - Tracking – adjusting space between all of the characters (c h a r a c t e r s) - Leading – amount of vertical space between lines of text (measured in either positive or negative points or zero) o “Loose Track” = more space between all characters o “Tight Track” = less space between all characters) o How to do kerning/tracking in Photoshop: In character tab, highlight characters you wish to change - RULE: to read easier, distance between lines should be greater than distance between words - Size – points (word processing) vs. pixels (8pt. 10pt, 10px, 36pt.) o Pixels are a measurement for text and images for the web on a monitor o Pixel is the smallest discrete component of an image or picture on a monitor o Point - A linear unit measuring the size of text in a word processing document o Points are a print unit of measure (word processing) o 72pt = 1inch when printed o 1pt = 1/72inch when printed o 11 pixels ≠ 11 points Font Types - Serif – tails, script, used for body paragraphs (ex: Times New Roman, Courier New, Century Schoolnook, Palatino) - Sans-Serif – no tails, block oriented, used for headings and titles (ex: Arial, Verdana, Helvetica, Arial Black, Comic Sans MS) Text Guidelines - Readability: Is the text easy to read? Avoid dark text against dark background - Complementary: Does the text complement the graphics? - Colour Coordination: Choose text that co-ordinates with any graphics - Balance: Position text carefully to achieve a good balance - Text Layout – simple, clear, white space - Mood: Set the mood using appropriate font attributes and layout Poster and Web Design guidelines (CRAP Principles) - Contrast  for emphasis; make 2 elements either similar or dissimilar by altering font, color, font size, effect(s) etc. - Repetition  repeat some aspect of the design throughout the design (i.e. bold font, thick rule, bullet, colors, font types) - Alignment  items are aligned – creates stronger cohesive unit - Proximity  group related items together Design Considerations - See everything, overlook a great deal, improve a little - Between two evil, choose neither, between two good, choose both - Give with no strings attached and you will receive in the same manner Lecture 3: Graphics Intro to Graphics - Rely on images for information, explanations, and entertainment - Where did images originate? o Non-digital medium (paper copy of a photo)  scanner saves the image in a file on your computer o Outside world (photography)  digital images uploaded to a file on your computer o Crate image (clip art images/scenes)  save images to a file - Computers only understand/speak “binary” (digits 0 and 1) - Your data gets stored in a series of 0s and 1s Digitization - Digitization refers to the process of translating a piece of information (analog) into binary bits (Binary Digits) (Digital) - Why? Computers are built from electronic devices that have only two possible states- On (High volt is a 1) or Off (Low volt is a 0) - Conversion from analog to digital - Binary (2 binary digits or bits), octal (8 digits, decimal (10 digits), and hexadecimal (16 digits)  we are only going to use binary! - How many items can we represent with binary bits? o If we have 1 bit, we could represent max of 2 values o If we have 2 bits, we could represent max 4 values o If we have 3 bits, we could represent max 8 values - If a pixel color is represented by 1 bits, value 0=black and value 1=white (1 bit allows for 2 colors) - If a pixel color is represented by 2 bits, value 00=black, value 01=grey, value 10=light grey, value 11=white (2 bits allow for 4 colors) - Rule: More bits we use, the moxe colors available to assign to a pixel - FORMULA: With x bits, 2 = y values - Digitization, converting from analog to digital, is a two-step process: 1. Sampling process  how often do I take a sample (measurement) to represent the “thing”, how many pixels will I break the “thing” (image, sound, video, animation, text, etc.) up into to get something clear 2. Quantizing  How many discrete values will I use to represent “each part” of the “thing”, represents the color combinations, how are colors coded - When images taken from a scanner, digital camera, or graphics application are stored on a computer, it is represented by a grid of squares called pixels (picture elements) - Pixel is the smallest image component and thus shows the smallest detail - Trend: the more samples taken, the clearer the picture becomes (makes pixels smaller and - Each pixel is given a numerical value that represent the corresponding color  If we have a 1 bit system to represent the color of each square, only have 2 colors  If we have 8 bits, we have 256 colors  If we have 24 bits, we have 16 million colors - How many bits do we need to represent text? Based on 8 bits (8 bi8s=1 byte) - How many possible combinations can we have using 8 bits? 2 = 256 values Colour Model - Used for Web – Additive Model (RGB) with primary colors red, green, blue  “Adding” light to a black background in order to obtain color shades - Used for printing – Subtractive Model (CMYK) with cyan, magenta, yellow  Uses printing ink – when applied to paper removes (“subtracted”) from a white background - Why use RGB rather than CMYK model for web? Since cathode ray tube devices, such as computer monitors, display color with red, green, and blue light, this is the color system for the web 24 - “True Color” – uses a 24 bit color representation (2 =16 million colors) - When we assign a color to a pixel, color can be expressed in: 1. RGB code  each pixel is represented by 3 values (ex: light yellow=<255,255,127>) where each value represents Red, Green, Blue  0 represents no amount and 255 represents max amount  Red = <255,0,0>  Green = <0,255,0>  Blue = <0,0,255>  White = <255,255,255>  Black = <0,0,0>  Need 3 bytes for true color (1 byte of red, 1 byte of green, and 1 byte of blue) 2. Hexadecimal code  notation is #RRGGBB where we use FF as full (255 in RGB)  #FF0000  Red  #00FF00  Green  #0000FF  Blue  #000000  Black  #FFFFFF White - Are RGB <66,00,99> and Hexadecimal = #660099 the same color? NO!!! - How many colors can the human eye detect? a) Less than 100‟000 b) About 1 million c) About 10 million d) About 100 million e) About 500 million Types of Graphics - graphics are categorized as being either Bitmap or Vector - Type of graphic affects how the graphics are displayed on a computer screen in terms of 1. Quality 2. File size 3. Time to display graphics - Raster is another name for Bitmap graphics - Bitmap images are made up of small squares called pixels - Editing pixels = changing color, shade and brightness - If you start with a small image (100.100px)  Assumption: as the image is made larger by resizing not zooming  Squares become larger, edges more jagged  Quality decreases  File size increase - Advantages of a small image on the web:  Shorter time needed to display it on the screen because file size is smaller - Vector Graphics  Image is represented with lines and arcs that have a mathematical relationship  Describing the drawing of the shape  To draw a: line – starting point, direction, length / rectangle – stat point, width, height / circle – centre and radius - Vector graphics - It doesn‟t matter what the size of the image is  As the image is resized larger or smaller  Edges become jagged  No distortion going up/ down in size  Quality is maintained  File size increases (if resized larger)  Advantage: ideal for producing artwork which frequently needs to be presented in different sizes or colors - Vector-based  Suitable for drawing that will be sized often  Greater control and precision with free-hand tool  Display more accurately on screen/paper/billboards (can be redrawn with accuracy without loss of quality)  Download faster – because of .svg format (less info recorded smaller file)  Must use “draw” program – draw and edit paths  Adobe Illustrator or Macromedia Freehand, Corel Draw  Common formats: .eps, .cdr(CorelDraw), .dwg (Autocad - Bitmapped- Based  Images from scanners, cameras, etc  Ability to edit an image‟s pixels  Need a “paint” program  PhotoShop, PaintShop Pro, PhotoPlus, Corel PhotoPain, Fireworks  Photoshop v6.0 – has vector features as well  Common bitmap file formats: .jpg, .gif, .png, .tiff, and .bmp  It is possible to convert vector to bitmap but not bitmap to vector - What affects image quality?  Image resolution  Image bit depth - Image Resolution  The number of pixels per square inch  Controlled through graphics package when asked to create an image  For web: set to 72 ppi  Lower resolution, smaller file size, faster download time  For printing: set to 300 ppi or more  Higher resolution means bigger file size  More pixels gives you a finer, less blocky result - Image Bit depths (color depth)  Refers to the number of bits used to represent a color of a pixel (ie 1 bit, 2 bits, 3 bits, etc)  1 bit – 2 colors (values 0,1 = black, white)  More bits you use, the more color info is stored to describe the color of a pixel  quality and file size increases How are images used? o For printing in a flyer or magazine  #1 - Quality  #2 - File size doesn‟t matter o For web page  #1 - File size matters  #2 -Quality  On the web, it‟s survival of the fastest- don‟t make me wait!  Objective on the internet o Download the website as quickly as possible  speed & file size & quality  Challenge: make sure image have smaller file size, keep the Quality and download fast. How? OPTOMIZE the image! Reduce the download time  How long will it take the image to download if we are using it in a webpage o If the client is using a high speed connect at 1500 kilobits per second: 33 seconds  most people have high speed connection o If the client is on a modem that is 56 kilobits per second : 14.33 minutes o On a really old modem that is 28.8 kilobits per second: 28.66 minutes  Problem: o Image size isn‟t appropriate o Doesn‟t look good o But downloads fast because it is small  Solution: o Choose the appropriate size needed and then use IMAGE OPTIMIZATION techniques o Goal: Download the web page fast. How? Make it a smaller file size without compromising quality of the image  Optimization Techniques o File formats: choosing .jpg or .gif o Compression: compress the image data o Color resolution: # of colors used (24 bits, 16 bits, 8 bits)  To reduce file size  choose a file format appropriate for the web  ONLY: .gif, .jpeg, .png  GIF properties o Graphics Interchange Format o Common image format used on the internet o Cross platform o Supports a max of 8-bi8 color scheme  8 bits/pixel (2 = 256 colors)  Thus good for clipart but not good for photos o Best for large areas of solid, flat color uses: illustrations, logos, text as graphics, cartoons, buttons o Tiny file sizes in comparison with .jpg o Saving an image with 24 bit color as a gif will lower the quality the first time you convert it to a gif o Summary: smaller file sizes but 256 colors o Allows for animation o Don‟t need a plug in for gif animation o Works in all browsers, universal format  JPEG o Joint Photographic Experts Group o Common image format used on the internet o Cross platform o JPEG stores full color information  Supports max of 24 bits/pixel (16 million colours)  Good for photos, computer games, screenshots, stills from a movie, etc..  Best for blends of color, softer shadow effects, subtle changes in color  Not for well-defined lines or sharp contrasts between colors24 o Larger file sizes in comparison with .gif (because of bit depth of 2 ) o Larger file sizes but Full color scheme  .jpg -distorts edges where there is a sharp contrast  .gif – larger areas of solid, flat color  To reduce a file size  choose a compression technique appropriate for the web  Role of Compression is to: o Reduce the redundancy of the image data in order to be able to store or transmit data in an efficient form o Compress as much as you can without sacrificing quality (by losing bits information)  Lossless: Every time you do a File >Save: o Compress the original bits and bytes into less bites and bytes without loosing any of the original information about the image o When we reopen the file, all the original information about the picture is still there o No information is lost  Lossy: Every time you do a File> Size: o When compression occurs, some of the original information is lost o Discards selected portions (that are least missed or noticed) of the image o Cannot get this info back once it is discarded  Each different type of image file format represents the use of a different compression algorithm  Common compressed algorithms .gif, .jpg, .png  .GIF  lossless compression, no data is discarded during compression, quality is kept  .JPG  lossy compression, data is discarded each time file is compressed, quality degrades  Uncompressed file formats: o .bmp (for Windows) o .raw (common on digital cameras)  .GIFs – Lossless compression o Does not get blurry or messy o Uses a simple technique called LZW compression to reduce the file sizes of images by finding repeated patterns of pixels o This compression never degrade the image quality  JPGs- “Lossy” compression o When you save an image as a JPEG file, not all of the information in the original image is preserved – not the same as the original – discards data o Degrades the image quality, each time you save o Compression is achieved by deleting certain details about the image, which the JPG will then try to fill in later when it is being displayed  The designers of the JPEG compression algorithm realized that the human eye is more sensitive to brightness details than to fine color details  Thus JPG conversion programs: o Try to save information about the brightness o If it finds two adjacent pixels with very similar colors, it will store both those pixels with the same color and discard the other color  When saving a JPEG image, you can select the quality or compression ratio of the final image  Application uses a complex compression algorithm based on the ratio value to determine “how much to discard”  Tip: because image data is lost with each compression, work with the image in native format (such as .psd) and when ready with final product, save it as a .jpg image  Observations o 1) The quality of a JPEG file is proportional to the file size o 2) Higher compression values  Reduces file size  Lowers quality of image  Less data being discarded Colour Resolution (Bit Depth)  Colour resolution is analogous to the number o8 colours  Remember: Gif‟s only support 8-bit colour (2 =256 colours)  Colour resolution = bit depth (what kind of representation are we using for the bit depth)  How do we do this?  In Photoshop, choose File > Save for web and devices  Reducing the image size lets it download faster  With .GIF files, we can look at dithering, interlacing, and transparency  With .JPG we can look at a Progressive jpeg  Dithering  o What do you think a program that coverts images into gifs does if the image has more than 256 colours? o Dithering – can lower download time, applies to when we convert a jpg to a gif o Instead of using “true” colour, we reduce the picture to the 256 colours or less o Dithering is the most common method of reducing the colour range of .jpg images down to the 256 or fewer colours o When you dither, you are reducing the colours and adding graininess to the image! o Final image is stored as a .gif o How does dithering work?  Juxtaposing (contrasting, placing side by side) pixels of two colours to create the illusion that a third colour is present o If an image uses colour outside of the browser-safe palette, the browser automatically dithers the displayed images into browser-safe colours  Interlacing Technique o Does not optimy your image, however it gives you the illusion that the file is downloading fast o Interlacing is what we use for .gif, and progressive interlacing is what we use for .jpgs o Is a process by which the image is drawn in a series of passes rather than all the same time o Best to use when image file sizes are really big o Benefits – interlacing lets you have a feel for the whole picture while you wait  Transparency o Applies to .gif and .png files only o Allows the page background to display through the image so the image appears to have no visible border around it o Allows for transparency of ONE COLOUR! Means that every pixel of that one colour will be completely see-through o Transparent – every pixel in the image is either completely visible or completely see-through so that what‟s “underneath” the image shows through  PNG files o Created specifically because of licensing issues with Gifs in the 90s due to legal issues resulting from GIFs compression scheme o Does LOSSLESS compression – no discarded information during save o Two versions of PNG  PNG-8 (8-bit colour system) and PNG -24 (8-bit colour system) o PNG-8  similar to GIF, allows for 256 colours, allows for 1 transparent colour o PNG-24  allows for 16 million colours, lossless compression so PNG- 24 file size will always be larger than jpg files, allows for transparency and translucency (provides various levels of where the background can bleed through o While transparent allows every pixel in the image is either completely visible or completely see-through so that what‟s underneath the image shows through, Translucent allows pixels that can be somewhat opaque to create a ghostlike, partially see-through effect Questions:  How big will an image be in terms of bytes if it is uncompressed, true colour, and 200 by 400 bytes? 200x400=80‟000  What type of compression doesn‟t lose any of the original information about the image? Lossless  Which types of file formats perform a lossless compression? PNG and GIF  JPG‟s will produce a smaller size than PNG-24 photograph. True or False? TRUE Capturing Digital Images:  Where do we get our images to use on our computer? Scanner, digital camera, and drawing  Scanner  o Converts from analog to digital o The scanner or the camera determines how many samples to take (how finely to break down the images) o More samples, the higher the resolution will be o Samples on scanners are measures as dots per inch (dpi) – higher the dpi, more samples o Example: if we can an 8 by 10 inch image with 100dpi, we will have (8x100) x (10x100) = 800 x 1000 = 800‟00 samples o If we print the scanned image, what will the print size be? Printing resolution is measures as ppi (dpi) o Formula: (physical image size) print size dimensions (in inches) = pixel dimensions of image / print resolution (ppi) o How do we set dpi for printing? In Photoshop, go Image>Image Size, Deselect Resample size and change the resolution  Digital Camera  o Advertised by megapixels  how many millions of pixels you can capture in a photograph on your digital camera (more pixels = higher resolution) o Megapixel – how many millions of pixels you can capture in a photograph o Describes the max size of an image (width x length) in pixels o Print size = pixel dimension / print resolution o Thus, a camera with more megapixels can print a larger image without the human eye detecting a loss of quality o If you want to print a 4” by 6” images, you don‟t need much more than 3 megapixels  Images on Screens o Monitor and Screen Resolutions – refers to the dimensions of the pixels displayed on the screen o A resolution of 800 x 600 will make the screen 800 pixels wide by 600 long o Higher Resolution: everything appears smaller, covers a portion of desktop, text harder to read o Lower resolution: every appears larger, covers entire area, text easier to read o Question: if image is 300 pixels by 200 pixels, and screen resolution I 640 by 480, 300 x 200 = 60‟000 and 640 x 480 is 307‟200 is about 20% of screen Questions: 1. What should you set the dpi for an image you with to print? Answer: set printer resolution at 300 dpi. When printing images you should set your printer resolution to 30 2. If you have an image that is 400 pixels by 600 pixels and the printer resolution is 200 dpi, what size will it print? Answer: 400/20 0 = 2 and 600/200 = 3, thus image is 2x3inches 3. If you want to print an image at 5by7 images, what is the minimum size it must be in pixels for it to not look pixelated? Answer: 5 inches x 300dpi = 1500 pixels, 7 inches x 300dpi = 2100 pixels, therefore 1500x2100 pixels 4. If I have an image that is 600px by 900px and I print it at a resolution of 150 dpi, how big will the image be? Answer: 600/150 = 4 inches 900/150 = 6 inches, therefore image size is 4x6 inches 5. How many megapixels is an image that is 2000px by 3000px? 2000x3000 = 6‟000‟000 pixels, thus 6megapixels Lecture 5: The Internet and WWW What is the Internet?  What you need to know when working in the world of website development: 1. Choose a Domain Name – how to brand your website 2. Order Web Hosting – put files on the system 3. Meet with Client – ensure you address all their needs 4. Create the Web Site – Dreamweaver HTML file  How does DATA travel? The Internet is the backbone for how data travels  Group of millions of computers around the world that are connected to one another  Network - a group of interconnected computers (could be connected with wires, wirelessly, satellites, etc.)  Any company that allows you to upload a file to a server and allows it to become internet ready is a host  Internet – an interconnection of computer networks, a network of networks  What is the Internet?  A global system of interconnected computer networks that use the standardized Internet Protocol Suite (TCP/IP) to serve billions of users worldwide How does it work?  TCP/IP  a standard protocol (Transmission Control Protocol) that sets rules for the format and transmission of data  The ideas behind this protocol were funded by the ARPA of the Us Department of Defense (DoD), thus the Internet was originally called the ARPANET  The Internet is hardware, the World Wide Web is software that runs on the Internet  How does one connect to the Internet? An Internet service provider (ISP) by modem, high-speed, etc. (examples include Rogers, Bell, UWO, etc.)  Circuit Switching – the entire package, or manuscript, of data gets sent through one process (how phone lines work)  On the Internet, data is sent by transferring packets (a small groups of bytes consisting of a Header, knows the destination and source, and the body, actual message content)  known as Packet Switching  Circuit switching (all data at once) vs. Packet switching (data split up) What is TCP/IP?  TCP – Transmission Control Protocol that sets rules for the format and transmission of data  How the TCP Works Sending End – 1. Take a large chunk of data and breaks it into smaller packages 2. IP is responsible for sending the packets out on the Internet Receiving End – 3. Detects lost packets, error packets because of network congestion, traffic load balancing, etc. Thus, requests the packet to be resent from the source. Then rearranges and reassembles the packets back into webpage, email message, etc. on the receivers machine  IP (Internet Protocol) is like a GPS that picks a route for a packet, stopping at routers which pick the next best machine/network to send the packet to (the router is the central switching device)  If a communication line is down or broken, sends the packet back to TCP and TCP sends it again to try a different route  Needs to be able to identify all machines on the internet, thus each machine has it‟s own unique address called an IP Address  Summary: 1. TCP breaks webpage into packets of bytes 2. TCP figures out IP address of where it wants to send the packets (destination) 3. TCP figures out IP address of where the packet is coming from (source) 4. Sends off each packet to the first machine (IP Address) on the route (does not preplan route) 5. Packet stops at first machine, likely a router, then the router sends it to the next machine on the journey (IP Address) and so on until it goes to the final IP address (destination) 6. Called Packet Switching! What is an IP Address?  An IP address identifies each computer or device connected to the internet (it‟s like a home address)  Every computer that connects to the Internet has an IP address  Notation – consists of 4 numbers with dots between them that range from 0 and 255 (ex:  IP addresses are not geographical so just think of this as an analogy; this is not exactly how this is done!  IP address expressed in different notation: Dotted Quad (notation we most often use since it is the simplest), Binary, Hexadecimal, and Decimal  Since we can‟t remember IP addresses easily, we use domain names What is a Domain Name?  What is a domain name? Text name corresponding to the numeric IP address of a computer on the Internet  Note: the WWW is NOT part of the domain name  Since every machine on the Internet has an IP address, a DNS (Domain Name System) maps the domain name to the correct IP address so data can route to the correct computer  Can have 1 IP address to 1 domain name, 1 IP address to many domains, or one domain name to many IP addresses  URL (Uniform Resource Locator) – is an address of a web document on a computer, every webpage is referred to by a URL, also known as the website address  Tim Berners Lee established the URL designation Rules for Domain Name  Example: o Http (Hypertext Transfer Protocol) – rules that define how data is exchanged between servers and browsers, says to use the hypertext transfer protocols o www (World Wide Web) – indicates file is on the World Wide Web o – domain name, the name of the website, points to the web server o /its/courses/ - It is a folder on the web server machine o spring.html – is a webpage file  Subdomains – used to organize your web server (just like folders and directories organize your computer)  Example: subdomain of main UWO website  Rules: max of 127 subdomain labels, each label can be a max of 63 characters, and whole domain cannot exceed 255 characters including the TLD (Top Level Domain)  Example: o Year2005 – subdomain, 4 level rd o Mycorvettes – subdomain, 3 ndvel o Mycars – domain name, 2 level o Com – top level domain (TLD)  Domain Name History: o 1973 – IP addresses became the standardized o 1984 – name servers that maps name to an IP address o 1985 – domain name system is established and the initial top level names are introduced o 1990 - Internet moves beyond government o 1995 – need to start paying for domain names o 1998 – assignment of domain name is opened up to private companies to encourage competition Starting a Business  Competition is fierce, thus a website is essential and expected  Websites: o Reach potential customers o Provides details on services/products providing o Allows window shopping into a business  By building a website, we are putting the customer in the driving seat  Websites allow customers can do their own research without needing to meet sales people as they work down to a short list  Permission marketing means customers decide who they will listen to and who they refuse to listen to  Successful businesses take full advantage of the Internet  Pierre Omidyar, created eBay (Echo Bay Consulting)  Setting up a website: 1. Choose a Domain Name – how to brand your website 2. Order Web Hosting – put files on the system 3. Meet with Client – ensure you address all their needs 4. Create the Web Site – Dreamweaver HTML file  Domain Name rules: o Max of 67 characters o 0-9, a-z o Dash character allowed (“-“), underscore invalid (“_”) o no spaces o Cannot start/end with dash o Case insensitive  What TLD (Top Level Domains) do I pick for my domain name? o .com  commercial business and companies o .net  Internet administrative site, network providers o .org  non-profit organizations o .edu  educational institutions o .gov  government agencies o .info  information o .biz  business o .ca  website in Canada o .eu  website in Europe  There is a cost for securing a domain name  Need to check the availability before making the website Picking an ISP  Web hosting: the service that provides Internet users with online systems for storing info, images, video, or any content accessible via the web  Web hosts: companies that provide space on the server they own for use by their clients as well as providing internet connectivity  Remember to shop around for best price and most reliable server  Top 10 reasons when picking an ISP: 1. Web Provider  reliability? How long? Popular? 2. Tech support  Test by sending them an email and see response time, contact names, emails, phone numbers, hotlines 3. Disk space  always get more, standard 5GB-10GB 4. Bandwidth  amount of traffic to your website 5. Web site speed  if slow, poor service 6. Uptime  look for 99% plus guaranteed 7. Database/programming language support  needs for dynamic website – interact with customers. Perl, Java, PHP, etc. 8. FTP Access  Unlimited and unrestricted FTP access for easy maintenance 9. Web Statistics Summary  Traffic on your website – easy access to your information… control 10. Script availability  counters, forms support  4 Reasons NOT to host your own website: 1. Expensive  server and server software can be expensive 2. Continual Connection  server needs 24/7 high speed connection which is relatively costly 3. Technical  setting up all the configurations including mail server, FTP server and DNS can be complicated 4. Support  server maintenance requires 24 hour support, special skills and knowledge Lecture 6 – Website Creation Concepts Stage 1: Planning and Design  Questions to ask  who is the audience? What is the company‟s image? Will the company focus change over a year? Logos? Graphic images? Check the competitor‟s site, do they have a domain name? Do they have a web host? Are there any sites that they like? Menu options on the
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