Internet_Edward_2020_957bd27ac6bea8805b77fadc8d58e55f.pdf

The Internet EDWARD.C. MWALIMU 9/24/2019 EDWARD CHANDA MWALIMU What is the Internet? The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/ IP) to serve billions of users worldwide. The INTERNET is a network of computers, which links many different types of computers all over the world. 9/24/2019 EDWARD CHANDA MWALIMU Definition of the Internet Cont’ It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope. They are linked by a broad array of electronic, wireless and optical networking technologies. 9/24/2019 EDWARD CHANDA MWALIMU History of the Internet The Internet started in the 1960s in USA. During the cold war between USA & Russia. The project Agency called Advanced Research Projects Agency (ARPA) was established to over see the project 9/24/2019 EDWARD CHANDA MWALIMU History Cont… In 1969 the project developed first computer network which was called ARPANET ARPANET was only used by Organizations in the defence forces in the U.S.A These defence forces were able communicate through this network 9/24/2019 EDWARD CHANDA MWALIMU History Cont… The e-mail was first sent on this network in 1972 by Tomlinson (Director of ARPANET) oThe message was just meaningless letters (QUERTYIOP) 9/24/2019 EDWARD CHANDA MWALIMU History Cont… Open Access Networks Because ARPANET was restricted to Defence, public networks were developed in the U.S.A These include the Southeastern Universities Research Association network (SURAnet) Provided networking services to universities and industries 9/24/2019 EDWARD CHANDA MWALIMU History Cont… Open Access Networks Another network called the Computer Science Network (CSNET) was developed in1981 in the U.S.A Its purpose was to extend networking benefits, for computer departments at academic and research institutions that could not be directly connected to ARPANET 9/24/2019 EDWARD CHANDA MWALIMU History Cont… Later in 1985, the National Science Foundation Network (NSFNET) was born in the USA to extend ARPANET, SURAnet and CSNET This was sponsored by the National Science Foundation (NSF)to promote advanced research and education networking in the United States 9/24/2019 EDWARD CHANDA MWALIMU History Cont… In 1990, ARPANET was decommissioned and NSFNET became the Centre of the Internet Congress liberalized access in the 1990s and this allowed networks from Canada and France to connect to NSFNET 9/24/2019 EDWARD CHANDA MWALIMU Governance of the Internet The Internet Corporation for Assigned Names and Numbers (ICANN) is a NGO that coordinates the Internet's global domain name system. CANN's primary responsibility is to ensure operational stability of the Internet; to promote competition; 9/24/2019 EDWARD CHANDA MWALIMU Governance of the Internet Cont.. Achieve broad representation of the global Internet community; develop policies appropriate to its mission through bottom-up, consensus-based processes. ICAN, through IANA (Internet Assigned Numbers Authority) is responsible for assigning Domain Names (IP addresses) to all Machines and information resources on the Internet. 9/24/2019 EDWARD CHANDA MWALIMU Basic services of internet Electronic mail FTP Telnet Usenet news The World Wide Web 9/24/2019 EDWARD CHANDA MWALIMU Electronic mail It enables to send and receive a mail (message). It is also known as e-mail in short It is Faster than paper mail. Images, audio, video can be sent along with text. Unlike Fax documents , Email documents can be stored in a computer and be easily edited using editing programs. 9/24/2019 EDWARD CHANDA MWALIMU File transfer Protocol (FTP) It enables users to move a file from one computer to another computer. A file may contain: ◦Text document ◦Image ◦Artwork ◦Movie ◦Sound ◦Software 9/24/2019 EDWARD CHANDA MWALIMU Telnet Telnet service enables users to login to another computer on internet from their local computer for using: ◦Database of remote computer This action is called ‘remote login’. 9/24/2019 EDWARD CHANDA MWALIMU Usenet News Usenet news service enables a group of internet users to exchange their views, ideas, information on some common topic of internet. A newsgroup is like a large notice board accessible to all members belonging to the group. 2 types of newsgroups: ◦Moderated ◦Non-moderated 9/24/2019 EDWARD CHANDA MWALIMU What is the World Wide Web (W3)? 9/24/2019 EDWARD CHANDA MWALIMU The World Wide Web The web is not the Internet It is basically a system of interlinked hypertext documents accessed through the Internet. It is a most popular method of accessing internet. It uses a concept called hypertext. Hypertext documents on internet are known as web pages. Web pages are created by using a special language called Hyper Text Markup Language (html) 9/24/2019 EDWARD CHANDA MWALIMU History of The World Wide Web (W3) In 1989, Lee a physicist began looking for ways to share documents, image and multimedia on the Internet. By then he was working for European Particles Physics Laboratory. In 1991, he developed a language called Hypertext Mark-up Language (HTML) to use mark-up and link document on the Internet 9/24/2019 EDWARD CHANDA MWALIMU History of The World Wide Web (W3) Cont… The birth of HTML resulted in the development of web servers (where HTML contents should be stored) and web browsers ( software used to access web resources). Further, the web protocol called Hyper Text Transfer Protocol (HTTP) was developed to be used by browsers when requesting web pages from the Internet 9/24/2019 EDWARD CHANDA MWALIMU Uses of The Internet and W3 E-commerce Communication Research Collaboration Training/Education Entertainment Downloading of software 9/24/2019 EDWARD CHANDA MWALIMU Uses of The Internet and W3 in Libraries Web-OPAC Online reservation Web based borrowing Online renewal Online Inter-library Loans Internet based purchasing Online reference 9/24/2019 EDWARD CHANDA MWALIMU ARPANET Forefather of internet INTERNET Network of computers Basic Services e-mails, FTP, Telnet, Usenet news Uses of internet Communication, sharing, exchanging, informing, feedback and support. 9/24/2019 EDWARD CHANDA MWALIMU https stands for Hyper Text Transfer Protocol. The S stands for "Secure". If you visit a Website or web page, and look at the address in the web browser, it is likely to begin with the following: http:///. 9/24/2019 EDWARD CHANDA MWALIMU This means that the website is talking to your browser using the regular unsecured language. In other words, it is possible for someone to “eavesdrop" on your computer's conversation with the Website. If you fill out a form on the website, someone might see the information you send to that site. 9/24/2019 EDWARD CHANDA MWALIMU This is why you never ever enter your credit card number in an http website! But if the web address begins with https:// that means your computer is talking to the website in a secure code that no one can eavesdrop on. 9/24/2019 EDWARD CHANDA MWALIMU QUOTE The Internet is like alcohol in some sense. It accentuates what you would do anyway. If you want to be a loner, you can be more alone. If you want to connect, it makes it easier to connect. Esther Dyson 9/24/2019 EDWARD CHANDA MWALIMU Types of websites Website  A website, is a collection of related web pages containing images, videos or other digital assets.  A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet address known as a Uniform Resource Locator.  All publicly accessible websites collectively constitute the World Wide Web. 9/24/2019 EDWARD CHANDA MWALIMU Static website  A static website is one that has web pages stored on the server in the format that is sent to a client web browser. It is primarily coded in Hypertext Markup Language, HTML.  Simple forms or marketing examples of websites, such as classic website, a five-page website or a brochure website are often static websites, because they present pre-defined, static information to the user.  This may include information about a company and its products and services via text, photos, animations, audio/video and interactive menus and navigation. 9/24/2019 EDWARD CHANDA MWALIMU Dynamic website A dynamic website is one that changes or customizes itself frequently and automatically, based on certain criteria. Dynamic websites can have two types of dynamic activity: Code and Content. Dynamic code is invisible or behind the scenes and dynamic content is visible and fully displayed. 9/24/2019 EDWARD CHANDA MWALIMU Difference B/W Both  In static web pages the theme and content of web pages remained fixed and in dynamic web pages they changed according to run time. Browsing and loading of static web pages are more quicker than dynamic web pages because unlike dynamic web pages they do not required the request of server. 9/24/2019 EDWARD CHANDA MWALIMU Difference B/W Both  If file extension of a URL is in.htm or.html then it is a static web pages. While if it is in.php,.asp and.jsp then it is the example of dynamic web pages.  Static web pages are created through HTML language while dynamic web pages are created by the usage of PHP, JavaScript and Action script languages. 9/24/2019 EDWARD CHANDA MWALIMU Difference B/W Both  Static web pages plan is an easy and cheap method if you wants to create a static and non updating web pages. While dynamic web pages method is advisable if you have plan to update the content and material frequently. Changing the content in static web pages is a difficult task because you have to develop and upload a new page while in dynamic web pages server application do this automatically. 9/24/2019 EDWARD CHANDA MWALIMU SEARCH ENGINES A web search engine is a software system that is designed to search for information on the World Wide Web. It uses the keywords to search for documents that relate to these key words and then puts the result in order of relevance to the topic that was searched for. 9/24/2019 EDWARD CHANDA MWALIMU EXAMPLES OF SEARCH ENGINES 9/24/2019 EDWARD CHANDA MWALIMU IMPORTANCE A search engine helps you find an appropriate website for something you are looking for but don't know the URL but still need to find what you are looking for. After you type it into a search engine a bunch of URLs will pop up and you click on the 1 you think is most helpful. 9/24/2019 EDWARD CHANDA MWALIMU IMPORTANCE Cont’ With over 8 billion web pages available, it would be impossible to search for the information that is specifically needed. Hence search engines are used to filter the information that is on the internet and transform it into results that each individual can easily access and use within the matter of seconds 9/24/2019 EDWARD CHANDA MWALIMU TYPES OF SEARCH ENGINES CRAWLER BASED DIRECTORIES HYBRID SEARCH ENGINES META SEARCH ENGINES 9/24/2019 EDWARD CHANDA MWALIMU CRAWLER SEARCH ENGINE A crawler is a program that visits Web sites and reads their pages and other information in order to create entries for a search engine index. The major search engines on the Web all have such a program, which is also known as a "spider" or a "bot." 9/24/2019 EDWARD CHANDA MWALIMU DIRECTORIES Directories depend on human editors to create their listings or the database. Yahoo Directory, Open Directory e.tc. Human-powered directories are good when you are interested in a general topic of search. 9/24/2019 EDWARD CHANDA MWALIMU Hybrid Search Engines Hybrid search engines are search engines that use both crawler based searches and directory searches to obtain their results. Example:- Yahoo.com and Google.com 9/24/2019 EDWARD CHANDA MWALIMU Meta search engines These transmit user-supplied keywords simultaneously to several individual search engines to actually carry out the search. Search results returned from all the search engines can be integrated, duplicates can be eliminated. Example: Dogpile, Metacrawler 9/24/2019 EDWARD CHANDA MWALIMU DOGPILE Dogpile is a search engine that fetches results from Google, Yahoo! and includes results from several other popular search engines. 9/24/2019 EDWARD CHANDA MWALIMU How To Use Search Enignes + A “+” before a word in a search will locate for documents which definitely contain the word. - A “-” before a word will exclude that word from search. “” Placing words between quotation marks will search for phrase between the quotes. or Using “or” between search phrase will search each term separately. 9/24/2019 EDWARD CHANDA MWALIMU How to make a better search Keep it simple Think how the page you are looking for will be written Describe what you need with as few terms as possible Choose descriptive words 9/24/2019 EDWARD CHANDA MWALIMU What are Boolean Operators? 9/24/2019 EDWARD CHANDA MWALIMU Boolean Operators are used to combine logical expressions into complex expressions 9/24/2019 EDWARD CHANDA MWALIMU History of Boolean Operators Boolean Operators are named for British-born Irish mathematician, George Boole. 9/24/2019 EDWARD CHANDA MWALIMU Types of Boolean AND OR () – Brackets/Parentheses “” – Quotation Marks – Asterisk (Wildcard Symbol) NOT – (sometimes AND NOT) NEAR 9/24/2019 EDWARD CHANDA MWALIMU THE BOOLEAN OPERATORS / THE BOOLEAN MODIFIERS Boolean Operators Boolean Modifiers “ ”Quotation Marks AND ( ) Brackets/Parentheses OR * Asterisk (Wildcard Symbol) NOT NEAR 9/24/2019 EDWARD CHANDA MWALIMU And (+) “And” narrows your search by combining terms; searches for both terms. 9/24/2019 EDWARD CHANDA MWALIMU Or “Or” broadens a search to include results containing both of the terms you type in. 9/24/2019 EDWARD CHANDA MWALIMU Not(-) NOT is the command of exclusion. “Not” narrows a search by reducing search results based on the information you want to exclude. 9/24/2019 EDWARD CHANDA MWALIMU NEAR Returns pages in your search string with both terms within close proximity to each other on the page. Usually within ten words or less. For example, a search for " Sales near Management“ would turn up results in which the two words appear close together. 9/24/2019 EDWARD CHANDA MWALIMU “”Quotation Marks Use “ ” (quotation marks) around multiple terms to search for resumes that include the term included in quotes. For example, “UNIX programmer” will return resumes that include that specific term, rather than separate occurrences of the two words. 9/24/2019 EDWARD CHANDA MWALIMU ( ) Brackets/Parentheses Cont’ You might initially construct a command like this: IBM OR Oracle OR “Red Hat” OR Microsoft. These are large companies, so any search like this is likely to generate a large number of results. If you wanted to find just individuals who have reached Manager or Director level, then you might use the following command: “Manager” OR “Director” 9/24/2019 EDWARD CHANDA MWALIMU ( ) Brackets/Parentheses Cont’ To combine both commands into one search, we use brackets to tell the search engine that these are separate conditions. In order to tell the search engine that we want to see results containing either Manager or Director and also one of IBM, Oracle, Red Hat, or Microsoft, we group them like this: (“Manager” OR “Director”) AND (IBM OR Oracle OR “Red Hat” OR Microsoft) 9/24/2019 EDWARD CHANDA MWALIMU * Wildcard symbol The asterisk can replace one or more letters at the end of a word. This might help you search for something that can be phrased differently. Example: Develop* (would retrieve pages with the words Developer, Developing, Development etc.) 9/24/2019 EDWARD CHANDA MWALIMU AND - is used when we want both skill sets such as X AND Y OR - is used when we want any of the available options i.e.: X OR Y OR Z Bracket/parentheses () - is used when AND and OR functions are used in same string. i.e.: X AND (Y OR Z). The above search means X is mandatory and either of Y or Z will do. 9/24/2019 EDWARD CHANDA MWALIMU Quotation mark“—” is used when we are looking for exact phrases i.e. “technical architect”. This search will find resumes with exact phrase “technical architect” written in them. NOT - NOT is used when we don’t want a specific word in a resume i.e.: (X AND Y) AND NOT Z. 9/24/2019 EDWARD CHANDA MWALIMU Content Management Systems Content – any information published on a Web site, be it text, HTML, images, videos… Management – the workflow and processes in place to create, share, and control information during its lifecycle Systems – an application that enables the creation, collection, publishing, and presentation of content 9/24/2019 EDWARD CHANDA MWALIMU CMS’ Cont’ What is a Content Management System? A Content Management System (CMS) is a computer program that allows publishing, editing and modifying content on a web site as well as maintenance from a central interface (Sharma & Kurhekar, 2013) 9/24/2019 EDWARD CHANDA MWALIMU CMS Cont’ Content management is the way of organizing, categorizing, and structuring the information resources (text, images, documents, etc.) so that they can be stored, published, and edited with ease and flexibility. 9/24/2019 EDWARD CHANDA MWALIMU Basic characteristics Lifecycle management – creation, publications, archive, rollback Infrastructure for managing multiple persons to engage with the content. The basic participants in the CMS are: 9/24/2019 EDWARD CHANDA MWALIMU Basic characteristics Cont’ Content Editors (who decide what content to publish and where) Content Publishers (who publish the content on the web) Content Authors (who create the content for the web) 9/24/2019 EDWARD CHANDA MWALIMU Basic characteristics Cont’ Pre-written templates Central repository to facilitate access and reuse 9/24/2019 EDWARD CHANDA MWALIMU Some Popular CMS ’ 9/24/2019 EDWARD CHANDA MWALIMU Cloud Computing Cloud computing is the on-demand availability of computer system resources, especially data storage and computing power, without direct active management by the user. The term is generally used to describe data centers available to many users over the Internet. These services are offered from data centers all over the world, which collectively are referred to as the "cloud." 9/24/2019 EDWARD CHANDA MWALIMU 9/24/2019 EDWARD CHANDA MWALIMU TYPES OF CLOUD COMPUTING Software as a service (SaaS) End Users Platform as a service approach (PaaS) Infrastructure as a service (IaaS): 9/24/2019 EDWARD CHANDA MWALIMU Software as a Service End-User Just run it for me! Also known as On-demand Service. Is an application that can be accessed from anywhere on the world as long as you have a computer with an Internet Connection We can access this cloud hosted application without any additional hardware or software. E.g. : G-mail, Yahoo mail, Hotmail etc.., 9/24/2019 EDWARD CHANDA MWALIMU Characteristics of SaaS It can be accessed globally The software can be updated automatically All license holder users will have same version of software 9/24/2019 EDWARD CHANDA MWALIMU Platform as Service- Application Developers In the PaaS model, cloud providers deliver a computing platform and/or solution stack typically including operating system, programming language execution environment, database, and web server. Is a platform for developers to write and create their own SaaS i.e. applications. Which means rapid development at low cost. 9/24/2019 EDWARD CHANDA MWALIMU Characteristics of PaaS No need of downloading and installing operating System It saves Customers money It mainly deals for delivering operating systems over Internet Software can be developed, tested and deployed 9/24/2019 EDWARD CHANDA MWALIMU Infrastructure as a Service Network Architects Also known as hardware as a service. Is a computing power that you can rent for a limited period of time. Allows existing applications to be run on a cloud suppliers hardware. Cloud providers offer computers – as physical or more often as virtual machines – raw (block) storage, firewalls, load balancers, and networks 9/24/2019 EDWARD CHANDA MWALIMU Characteristics of IaaS Policy based Services Utility computing Services Dynamic Scaling Internet Connectivity 9/24/2019 EDWARD CHANDA MWALIMU Architecture 9/24/2019 EDWARD CHANDA MWALIMU Cloud architecture: Refers to the architecture of software systems involved in the delivery of cloud computing. It includes multiple cloud components communicating with each other. 9/24/2019 EDWARD CHANDA MWALIMU DATA Security in Cloud Computing Data outsourcing: users are relieved from the burden of data storage and maintenance. When users put their data (of large size) on the cloud, the data integrity protection is challenging. Enabling public audit for cloud data storage security is important 9/24/2019 EDWARD CHANDA MWALIMU user data user user External Audit party Cloud network 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing Cloud computing is built on top of virtualization, if there are security issues with virtualization, then there will also be security issues with cloud computing. Data segregation. Data in the cloud is typically in a shared environment alongside data from other customers. Encryption is effective but isn't a cure-all. The cloud provider should provide evidence that encryption schemes were designed and tested by experienced specialists. 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing A data center full of servers supporting cloud computing is internally and externally indistinguishable from a data center full of "regular" servers. In each case, it will be important for the data center to be physically secure against unauthorized access 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing Computer and network security is fundamentally about three goals/objectives: -- confidentiality (C) -- integrity (I), and -- availability (A). 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing Confidentiality refers to keeping data private. Privacy is important as data leaves the borders of the organization. Not only must internal secrets and sensitive personal data be safeguarded, but metadata and transactional data can also leak important details about firms or individuals. Confidentiality is supported by, among other things, technical tools such as encryption and access control, as well as legal protections 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing Integrity is a degree confidence that the data in the cloud is what is supposed to be there, and is protected against accidental or intentional alteration without authorization. It also extends to the hurdles of synchronizing multiple databases. Integrity is supported by well audited code, well-designed distributed systems, and robust access control mechanisms. 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing Availability means being able to use the system as anticipated. Cloud technologies can increase availability through widespread internet-enabled access, but the client is dependent on the timely and robust provision of resources. Availability is supported by capacity building and good architecture by the provider, as well as well- defined contracts and terms of agreement 9/24/2019 EDWARD CHANDA MWALIMU Data Security in Cloud Computing Reduces the exposure of sensitive data Simplifies security auditing & testing Enables automated security management Improves redundancy & disaster recovery 9/24/2019 EDWARD CHANDA MWALIMU Technologies used for data security in cloud computing Data Masking Technology (Confidential parts of data are deleted or changed before transmission.) Secure Logic Migration and Execution Technology (certain aspects of the data are concealed by simply defining the security level of data.) Data Traceability Technology (information gateway tracks all information flowing into and out of the cloud, so these flows and their content can be checked.) 9/24/2019 EDWARD CHANDA MWALIMU THANK YOU 9/24/2019 EDWARD CHANDA MWALIMU

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