Business Information Management PDF Lecture Notes

Business Information Management Dr. Michael P. O’Brien Module: MI4007 (Lecture 1 of 2) 1 What is the Internet? The Internet is a world-wide network of computer networks. It grows hourly and involves national governments, comm...

Business Information Management Dr. Michael P. O’Brien Module: MI4007 (Lecture 1 of 2) 1 What is the Internet? The Internet is a world-wide network of computer networks. It grows hourly and involves national governments, communities, and individuals. It is the largest network in the world that connects hundreds of thousands of individual networks all over the world. 2  The Internet: Then & Now Created in 1983 by the Advanced Research Projects Agency (ARPA) and the U.S. Department of Defense for scientific and military communications. The Internet is a network of interconnected networks. Even if part of its infrastructure was destroyed, data could flow through the remaining networks. The Internet uses high-speed data lines, called backbones, to carry data. Smaller networks connect to the backbone, enabling any user on any network to exchange data with any other user. ARPANET, NSFnet, Internet. 3 The Internet: Then & Now No one owns it. It has no formal management organisation. Internetworking: the process of connecting separate networks. Where is all the information? – It actually runs from one computer to another on servers, which are machines that share information across computers. 4  The Internet: Then & Now The Internet: Currently 5.35 billion users (2024) Provides “free” service Services provided – World Wide Web – E-mail – Voice over IP – File Transfer Protocol (FTP) 5 How the Internet Works 6  How the Internet Works The Internet includes thousands of host computers (servers), which provide data and services as requested by client systems. When you use the Internet, your PC (a client) requests data from a host system. The request and data are broken into packets and travel across multiple networks before being reassembled at their destination. Packets of information flow between machines governed by common rules (protocols): – Internet protocol (IP) – Transmission control protocol (TCP) 7 How the Internet Works The Internet is a packet-switching network. – Messages are decomposed into packets, containing part of the message, plus information on the sending and receiving machines and how the packet relates to the other packets. – Packets travel independently and possibly on different routes through the Internet. – Packets are reassembled into the message at the receiving machine. In order to communicate across the Internet, a computer must have a unique address. 8  How the Internet Works Every computer on the Internet has a unique numeric identifier, called an Internet Protocol (IP) address. Each IP address has four parts – each part a number between 0 and 255. An IP address might look like this: 205.46.117.104. The graphic below illustrates two computers connected to the Internet; your computer with IP address 1.2.3.4 and another computer with IP address 5.6.7.8. https://whatismyipaddress.com 9 Internet Service Provider How do individuals and organisations get the Internet? – They use an Internet Service Provider (ISP). An ISP is a company that provides Internet access for its customers. It may also provide e-mail service for its customers. It may provide web file storage service and/or a limited web hosting service. Examples include Eir, Virgin Media, Vodafone, Sky, Imagine. 10  Internet Service Provider Once the ISP has provided access, how does an individual computer allow Internet access? – Via web browsers: software programs that run on the user’s computer to connect you to remote computers, open and transfer files, display text and images. 11 What is the Web? The Web is a collection of files that reside on computers, called Web servers, that are located all over the world and are connected to each other through the Internet. When you use your Internet connection to become part of the Web, your computer becomes a Web client in a worldwide client/server network. The Web browser is the software that you run on your computer to make it work as a web client. A Web page is a document encoded with hypertext markup language (HTML) tags. HTML allows designers to link content together via hyperlinks. Every Web page has an address, a Uniform Resource Locator (URL). 12  Hypertext Markup Language (HTML) Hypertext Markup Language (HTML) is the standard language for creating web pages and web applications. Hello World This is a simple webpage Now the text is italics, not bold 13 Hypertext Markup Language (HTML) HTML uses codes, or tags, to tell the Web browser software how to display the text contained in the document. For example, a Web browser reading the following line of text: A Review of the BookWind Instruments of the 18th Century recognises the and tags as instructions to display the entire line of text in bold and the and tags as instructions to display the text enclosed by those tags in italics. 14  Domain Name Addressing Most web browsers do not use the IP address to locate Web sites and individual pages. They instead use domain name addressing. A domain name is a unique name associated with a specific IP address by a program that runs on an Internet host computer. This program, which coordinates the IP addresses and domain names for all computers attached to it, is called DNS (Domain Name System) software. The host computer that runs this software is called a domain name server. 15 Domain Name Addressing Domain names can include any number of parts separated by periods, however most domain names currently in use have only three or four parts. Domain names follow a hierarchical model that you can follow from top to bottom if you read the name from the right to the left. For example, the domain name gems.ul.ie is the computer connected to the Internet at the Graduate Entry Medical School (gems), which is an academic unit of the University of Limerick (ul), which is on the Rep. of Ireland Top-Level Domain (ie). No other computer on the Internet has the same domain name. 16  Uniform Resource Locators The IP address and the domain name each identify a particular computer on the Internet. However, they do not indicate where a Web page’s HTML document resides on that computer. To identify a Web pages exact location, Web browsers rely on Uniform Resource Locator (URL). URL is a four-part addressing scheme that tells the Web browser: Ø What transfer protocol to use for transporting the file Ø The domain name of the computer on which the file resides Ø The pathname of the folder or directory on the computer on which the file resides Ø The name of the file 17 Structure of Uniform Resource Locators protocol pathname http://www.chicagosymphony.org/civicconcerts/index.html Domain name filename http => Hypertext Transfer Protocol 18  HTTP The transfer protocol is the set of rules that the computers use to move files from one computer to another on the Internet. The most common transfer protocol used on the Internet is the Hypertext Transfer Protocol (HTTP). Two other protocols that you can use on the Internet are the File Transfer Protocol (FTP) and the Telnet Protocol. HTTPS stands for Hypertext Transfer Protocol Secure. It is the protocol where encrypted HTTP data is transferred over a secure connection. 19 General Operation of the Web Client Web Server Web Computer Browser Computer Server 1) A user enters a web address into the browser www.ul.ie/module.html DNS Server 20  General Operation of the Web Client Web Server Web Computer Browser Computer Server 2) The browser contacts a DNS server and gets the URL, in this case www.ul.ie, translated to an IP address. DNS Server 21 General Operation of the Web Client Web Server Web Computer Browser Computer Server 3) The browser contacts the web server and requests the file, in this case module.html DNS Server 22  General Operation of the Web Client Web Server Web Computer Browser Computer Server 4) The web server finds DNS Server the relevant file, and returns it to the browser 23 General Operation of the Web Client Web Server Web Computer Browser Computer Server 5) The browser takes the returned HTML file and renders it. DNS Server 24  Dynamic Web Pages Websites can be built using static pages – i.e. files we manually edit. But – that means every time something changes, we need to manually change it, someone has to go in with an editor and make the change. Obviously, not what happens… 25 Dynamic Web Pages A dynamic web page is a web page that displays different content each time it's viewed. For example, the page may change with the time of day, the user that accesses the webpage, or the type of user interaction. Two types: Client-Side Scripting Server-Side Scripting 26  Emerging Technologies (2024) 27 Emerging Technologies 1) Read the articles on Emerging Technologies on Brightspace. 2) Review the hype cycle for emerging technologies in the previous slide. 3) Think about the impact of some of these emerging technologies on business, the nature of work and the future of the job… 4) Opportunities? 5) Threats? 28 29