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Internet. Wendy G Lehnert, “ Internet 101, A Beginners Guide to the Internet and the World Wide Web ” ,Addison-Wesley, 1998 The Internet is simply a network of computers, linked together all over the world. A “ network of networks ” . size, history
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Internet • Wendy G Lehnert, “Internet 101, A Beginners Guide to the Internet and the World Wide Web”,Addison-Wesley, 1998 • The Internet is simply a network of computers, linked together all over the world. A “network of networks”. • size, history • http://www.isoc.org/internet-history/ brief.html
Ownership, no rules • “membership” by connecting to an ISP • Packet-switching model (origin, destination, file name, packet number) • LAN or WAN • Every network has a IP address (URLs) • Protocol://host computer/path/filename • major domain name edu,com,org,net,gov • country code au uk • Protocol defines the type of connection you make to the Internet. WWW-http
Protocols • A set of rules for communicating the end points in a telecommunication network use when they send signals back and forth • regardless of computer type • need internet connection, appropriate software • IP-internet protocol, TCP/IP-transmission control protocol, HTTP-hypertext transfer protocol, SMTP-simple mail transfer protocol, FTP-file transfer protocol, telnet, (video protocol?) • how we make connection http:// ftp:// telnet://
Caches and proxy servers • The cache is simply a temporary storage area where your browser stores files that it downloads. Using BACK button. • In Internet Explorer: temporary internet files under windows folder • Proxy server - cache provided by ISP, invisible to user, intermediary between user and Internet, filters requirements, looks at local cache, requests server on Internet on behalf of user
Firewalls • In computer networks used to control the material that passes between a network and the outside world. Mixture of hardware and software that acts as a buffer between your network and the rest of the Internet. The firewall controls access into and out of your network.
Web Pages • Web page uses hypertext markup language view-page source • home page (start of the book) • Frames - designated sections of a page with different source, URL: right click-properties • internet address - address of network • e-mail address - address of account • web page address - address of file
Searching the Web • Search Engine is a Web page which has been set up to allow you free web searching and support service. • Altavista: Advertising, find good content • search engine use a spider or crawler which work its way around the Web from link to link, collecting data to create a database. • Spider/crawler, a database, software query
Searching • Spider captures references to many web pages • out of date, moved location, account expired • syntax use on queries “…..”, multiple words, comput*, be specific, and/or/not, + - • hitlist, directory search engines (index of categories ), key word search engines
Favourites • Internet Explorer- Favorites • Netscape Communicator- Bookmark • URL and title, housekeeping • use official sites • referencingbooks: title, author, publication details, page number • referencing Web pages: URL, author, date found
Search within page:edit-find, search button • evaluating search engines: database, specific, search facilities • being found when creating a site: query words in title or start, close together, many instances of query words, list of search engines, requirements, let them know, include links • http://www.albany.edu/library/internet/second.html
Word Processing (2) • Document (.doc) has content ( text, graphics, charts) and form (appearance). • “This is a text file “Text.txt contains 21 characters (the 19 characters that we wrote, plus an end-of-line character and an end-of-file character), Word.doc contains 19456 characters! RTF contains 2582 characters. • RTF (Rich Text Format) it is a file format that allows you to exchange document files in text format between different versions of the same word processing software, Different word processing software packages, Different operating systems.
Word Processing (3) • Save, Save As, Autosave • .tmp file keeps new changes before saving • ASCII and Unicode • show/hide on toolbar for structure of layout • sections, margins in page setup • headers and footers, make tables, help option (contents-index).
Word • RAM (random access memory) and ROM( read only memory) with documents • Clipboard - temporary memory space • copy-paste cut-paste • Deleting, Undo, Redo button • Find ( can use * ? ) and Replace • Insert-symbols (special characters) • Clip Art and WordArt
Tools in Word • Spell checkers: language, technical and proper names, grammar errors of context, use of add button, • Grammar Checker - Auto Correct - Thesaurus • Properties of files to see statistics
HTML • HTMLis the language that most Web browsers use. • We say that most web pages are coded in HTML
HTML and Web Browsers • In this case, the "compiler" or document handler is your Web browser (Internet Explorer or Netscape) which is designed to handle text documents encoded with HTML tags.
How to start HTML • <html> • <head> • <title>First Marked up Document</title> • </head> • <body> • ………… • </body> • </html>
Backgrounds • <body background="htmlbg.gif" bgcolor="#ffffcc" link=#ff7777 text=#cccccc> • Declares background and default colours of background, text, and links in the web page.
Headings • the beginning and end tags are identical except for the forward slash (/) • <H1>Make your own Heading</H1> • <h2> smaller • <h3> and smaller • <h4> and smaller • <h5> and smaller • and • <h6> smallest
Formatting text • <font color="#FF0000"><font size=+2> ………….. </font></font> • <b><u><i> comp123 </i></u></b> • <hr WIDTH="100%"> draws a line • <center> </center> centres text • <br> and <p> line spaces
Images • <img SRC="Aobo.gif" height=118 width=350> • Make sure picture is in same folder as web page (html file) • The tag <img> has a number of attributes including "width", "height", "align“.
Links • <a href="http://www.opera-australia.org.au/”>link to opera page</a> • <a href=“page1.html”>link to Web Page 1</a> • <a href =“#Top”> go to top of page</a>
Lists • <li>............list item(puts a "dot" before each item) <ul>............unnumbered list <ol>............ordered list (numbers each item) • <ul>…</ul> or <ol>…</ol> • <li>item 1</li> • <li>item 2</li>
Tables • <table> .... </table> define a table • <th> specifies table heading • <tr> specifies rows in a table • <td> ... </td> define data contained in a cell • <table border=4 width=100%> • <th>Heading1</th><th>Head Cell 2</th><tr> • <td>Cell 3</td><td>Cell 4</td><tr> • <td>Cell 5</td><td>Cell 6</td> • </table>
toolbars • Picture - controls a selected image. You can use this to adjust the brightness or contrast of an image, or carry out other functions. • Office Clipboard - It used to be a fact that the clipboard could only hold one thing at a time. Using the Office Clipboard, as outlined in the text, allows you to store up to 12 different items on the Clipboard at once. • Tables and Borders - This can be used as another way of controlling the tables in your document; you don't have to go to the Table menu.
Fonts • Scaleable Fonts:can be adjusted to any size, and can be printed well on any printer that prints graphics. • Printer fonts are fonts that are built into the printer. True type or postcript fonts • Screen Fonts: In order to display a font on your screen, the font type and size must be installed in your computer. Screen fonts are bitmapped fonts.
Lists : ordered or unordered, flat or multilevel. An ordered list would be used when whatever is being listed should be numbered while an unordered list may be used for a list of related items which could appear in any order. • A normal list is flat, only one level, but it is possible to have a multilevel list (Outline Numbered List). • Mammals • Dogs • Labrador • Poodle • Horses • Dolphins
Paragraphs • “is any amount of text, graphics, objects or other items that are followed by a paragraph mark” (¶) • You insert a paragraph mark each time you press “Enter” • Wrap around - word wrap
Widow and Orphan Control • Widow: the last line of a paragraph printed by itself at the top of a page • Orphan: the first line of a paragraph printed by itself at the bottom of a page • Keeping lines together
Hyphenation • Allows more text to fit on a line • Improves appearance • Often used with full justification (e.g. newspaper columns) • In Word can choose automatic or manual
Headers and Footers • Puts vital information on each page • Can be text, drawing, page number, date, file name etc • Need to use sections to have different headers and footers (as in assignment) • Worth getting to know • Logos • First page
Templates • Master copy for all documents of a certain type • Can include text and graphics • Sets margins and document formats
Normal.dot • Times New Roman • 12 pt(in Word 2000) • Left aligned • Single spacing • ….
Customised Templates • Saved as .dot files • Easiest way to make a template:Open a document that has the formatting you want, and save it as a template • Task for you
Hidden text • Hides notes and comments in a document • Options • Can be seen on screen (or not) • Can be printed (or not) • Warning - be careful how you use it!
Mail Merge • Mail Merge can be used to merge any kind of data with any other kind of document to individualise the documents. • create a mail merge, need the data document and the merge document. The data document needs to be a tab-delimited or comma-delimited text file, which is simply a file with repeating fields that are separated ("delimited") by a tab character or a comma. Set up in MS Word, MS Access, MS Excel, or Outlook.
Data representation • Bits (smallest unit of information) 1 bit = 0 or 1 • Byte (8 bits) 1 byte: A single character • Kilobyte (approximately 1000 bytes) 1 Kilobyte: A very short story 2 Kilobytes: A Typewritten page • Megabyte (approximately 1 000 000 bytes) 1 Megabyte: A small novel 5 Megabytes: The complete works of Shakespeare 100 Megabytes: 1 metre of shelved books 650 Megabytes: A CD-ROM
Data representation • Gigabyte (approximately 1 000 000 000 bytes) 1 Gigabyte: A pickup truck (eg. Ford F250) with cargo area filled with printed paper to a depth of 40 cm. 20 Gigabytes: A good collection of the works of Beethoven 100 Gigabytes: A floor of academic journals • Terabyte (approximately 1 000 000 000 000 bytes) 1 Terabyte: 50, 000 trees made into paper and printed 10 Terabytes: The printed collection of the US Library of Congress • Petabyte (approximately 1 000 000 000 000 000 bytes) 2 Petabytes: All US academic research libraries 200 Petabytes: All printed material • Exabyte (approximately 1 000 000 000 000 000 000 bytes) 5 Exabytes: All words ever spoken by human beings. • How many bits / bytes in a floppy disk / CD-ROM /in 10 GB? • Conversion of binary to decimal
Representation standards • ASC II and Unicode • Conversion of characters, numbers and symbols to binary numbers • A = 100000001 B = 10000010 (1 byte) • ASC II limited to 256 (28) different variations or characters • A = 1000000000000001 (2 bytes) • Unicode limit is 65000 different variations
Memory, CPU • RAM - random access memory • volatile, temporary, fast access • ROM - read only memory • non-volatile, permanent, slow access, CACHE • The processor is called the CPU central processing unit • compatibility, speed, RISC (reduced instruction set computer) - IBM for Macs faster • CISC (complex instruction set computer) - Intel for Pentiums slower • Fetch instruction - Memory - Bus interface unit - pre fetch unit-decode unit- control unit- ALU arithmetic logic unit (registers of 32 and 64 bits)-sent back to memory • Machine cycle: instruction set is read - write - move –operate on data- make decisions • Algorithm that repeats forever: fetch instruction – increment program counter – decode instruction – obey instruction
Hardware • Buses (travel between components of the computer in 8, 16, 32 bits) • Ports (serial and parallel) • Peripherals - input, output, storage (hard disk, floppy disk, tapes, zip, CD ROM, DVD) • Moving data around - buses, ports, expansion slots, scsi drives • Buying a computer - what will you do with it? Cost – software- expansion
Software • Software: compilers software applications, system software • Compilers and translators - translate programs to machine language • Programming languages - C++ Java Basic • How CPU executes a program (adding 2numbers): • get (read) number at memory location x and place in register A, get another number, add contents of registers and put in register C, write (copy) register C to memory location y.
Programs • Integrated software: cheaper, transfer of data easier, feels and looks same • Public domain software, shareware, freeware • Proprietary software–licence(allowed to use the program,still property of the company) • piracy
System Software • Taking care of hardware issues relating to what you are doing in software • Operating systems: keeps hardware running efficiently, makes process of commun9icating with the hardware easier • communicate with peripherals, coordinates concurrent processing of jobs (multitasking), manages the memory, data and program management, monitors resources, accounting and security, coordinates network communications. • Multitasking is when the computer seems to be working on several programs at the same time (speed). • Utility software: tools for doing system maintenance and some repairs the OS can’t automatically handle. • Virus scan, fix corrupted data files
Operating System • MS-DOS, Macintosh, Microsoft Windows • User Interface- software (application) program - operating system (hardware) • Software compatibility (RTF) and reliability • OS lives in ROM and starts up computer with “booting” process. • Character based and Graphical User Interfaces (GUIs) – (advantages of GUIs) intuitive, consistent, forgiving, protective, flexible.
Bandwidth • bandwidth - amount of information cable can hold (allow to travel on it) • ISDN -integrated services digital network - callup digital line with 128Kbps • T1 and T3 direct digital with 1.5-3Mbps • Intranet – a small copy of internet at work inside the LAN/WAN network of a company. • Extranet – a private network between company and business clients
Linking Up: Network Basics • Why is networking important? • Cost • allows people to share hardware • Efficiency & Productivity • allows people to share data and software • Opportunity • allows people to work together in ways that are otherwise difficult or impossible
LAN (Local Area Network) • Network of interconnected workstations • Sharing common resources • Within a relatively small geographic area
Client-Server LAN • Server • Storehouse for software and data • Management of shared resources • Printers • Client • Computers that request server services
Peer-to-Peer LAN • There are no servers • Shared resources managed by all computers • Effective for small LANs