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    E commerce E commerce Document Transcript

    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH STUDY MATERIAL ELECTRONIC COMMERCE DEPARTMENT OF IT R S Vel Tech Vel Tech Multi Tech Dr.Rangarajan Dr.Sakunthala Engineering College Vel Tech High Tech Dr. Rangarajan Dr.Sakunthala Engineering College SEM - VIIIVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 1
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH INDEXUNITS PAGE NO.I. Unit - I 24II. Unit - II 30III. Unit - III 36IV. Unit - IV 42V. Unit – V 49 # 42 & 60, Avadi – Veltech Road, Avadi, Chennai – 62.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 2 R S
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH Phone : 044 26840603 email : veltech@vsnl.com 26841601 website : www.vel-tech.org 26840766 www.veltechuniv.edu.in∗ Student Strength of Vel Tech increased from 413 to 10579, between 1997 and 2010.∗ Our heartfelt gratitude to AICTE for sanctioning highest number of seats and highest number of courses for the academic year 2009 – 2010 in Tamil Nadu, India.∗ Consistent success on academic performance by achieving 97% - 100% in University examination results during the past 4 academic years.∗ Tie-up with Oracle Corporation for conducting training programmes & qualifying our students for International Certifications.∗ Permission obtained to start Cisco Networking Academy Programmes in our College campus.∗ Satyam Ventures R&D Centre located in Vel Tech Engineering College premises.∗ Signed MOU with FL Smidth for placements, Project and Training.∗ Signed MOU with British Council for Promotion of High Proficiency in Business English, of the University of Cambridge, UK (BEC).∗ Signed MOU with NASSCOM.∗ Signed MOU with INVICTUS TECHNOLOGY for projects & Placements.∗ Signed MOU with SUTHERLAND GLOBAL SERVICES for Training & Placements.∗ Signed MOU with Tmi First for Training & Placements.VELTECH, VEL TECH MULTI TECH engineering colleges Accredited by TCSVEL TECH, VEL TECH MULTI TECH, VEL TECH HIGH TECH, engineering colleges & VEL SRI RANGA SANKU(ARTS & SCIENCE) Accredited by CTS.Companies Such as TCS, INFOSYS TECHNOLOGIES, IBM, WIPRO TECHNOLOGIES, KEANE SOFTWARE & TINFOTECH, ACCENTURE, HCL TECHNOLOGIES, TCE Consulting Engineers, SIEMENS, BIRLASOFT,MPHASIS(EDS), APOLLO HOSPITALS, CLAYTON, ASHOK LEYLAND, IDEA AE & E, SATYAM VENTURES,UNITED ENGINEERS, ETA-ASCON, CARBORANDUM UNIVERSAL, CIPLA, FUTURE GROUP, DELPHI-TVSDIESEL SYSTEMS, ICICI PRULIFE, ICICI LOMBARD, HWASHIN, HYUNDAI, TATA CHEMICAL LTD, RECKITTBENKIZER, MURUGAPPA GROUP, POLARIS, FOXCONN, LIONBRIDGE, USHA FIRE SAFETY, MALCO,YOUTELECOM, HONEYWELL, MANDOBRAKES, DEXTERITY, HEXAWARE, TEMENOS, RBS, NAVIA MARKETS,EUREKHA FORBES, RELIANCE INFOCOMM, NUMERIC POWER SYSTEMS, ORCHID CHEMICALS, JEEVANDIESEL, AMALGAMATION CLUTCH VALEO, SAINT GOBAIN, SONA GROUP, NOKIA, NICHOLAS PHARIMAL,SKH METALS, ASIA MOTOR WORKS, PEROT, BRITANNIA, YOKAGAWA FED BY, JEEVAN DIESEL visit ourcampus annually to recruit our final year Engineering, Diploma, Medical and Management Students. Preface to the First EditionVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 3
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH This edition is a sincere and co-ordinated effort which we hope has made agreat difference in the quality of the material. “Giving the best to the students,making optimum use of available technical facilities & intellectual strength” hasalways been the motto of our institutions. In this edition the best staff across thegroup of colleges has been chosen to develop specific units. Hence the material, as awhole is the merge of the intellectual capacities of our faculties across the group ofInstitutions. 45 to 60, two mark questions and 15 to 20, sixteen mark questions foreach unit are available in this material.Prepared By : Ms. D. Anandhi.IT1007 ELECTRONICS COMMERCEUNIT I 9Introduction – Electronic Commerce Framework – The Anatomy of E-Commerce Applications.The Network Infrastructure for E-Commerce, The Internet as a Network Infrastructure.UNIT II 9VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 4
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHElectronic Payment Systems, Interorganizational Commerce and EDI, EDI Implementation, MIMEand Value – added Networks.UNIT III 9Advertising and Marketing on the Internet, Computer Based Education and Training,Technological Components of Education on-Demand, Digital Copy rights and ElectronicCommerce, Software Agent.UNIT IV 9The Corporate Digital Library – Dimensions of Internal Electronics Commerce Systems, Making aBusiness case for a document Library, Types of Digital documents, Issues behind documentInfrastructure, Corporate data warehouses, Documents Active / Compound documentarchitecture.UNIT V 9Multimedia and Digital Video – Broad band Telecommunications – Mobile and WirelessComputing Fundamentals.TEXT BOOK1. “Frontiers of Electronic Commerce”, Kalakota & Whinston, Pearson Education, 2002.REFERENCES1. Kamalesh K. Bajaj, “E-Commerce: The Cutting Edge & Business”, Tata McGraw-Hill, 2003.2. Brenda Kennan, “Managing your E-Commerce Business”, PHI, 2001.3. “Electronic Commerce from Vision to Fulfillment”, PHI, Elias M. Awad, Feb-2003.4. “Electronic Commerce – Framework, Technology and Application”, TMH, Bharat Bhaskar, 2003.5. Effy Oz, “ Foundations of E-Commerce”, PHI, 2001.6. Jim A Carter, “Developing E-Commerce Systems”, PHI, 2001. ELECTRONIC COMMERCEIntroduction Electronic commerce, commonly known as (electronic marketing) e-commerce oreCommerce, consists of the buying and selling of products or services over electronic systemssuch as the Internet and other computer networks. The amount of trade conducted electronicallyVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 5
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHhas grown extraordinarily with widespread Internet usage. The use of commerce is conducted inthis way, spurring and drawing on innovations in electronic funds transfer, supply chainmanagement, Internet marketing, online transaction processing, electronic data interchange (EDI),inventory management systems, and automated data collection systems. Modern electroniccommerce typically uses the World Wide Web at least at some point in the transactions lifecycle,although it can encompass a wider range of technologies such as e-mail as well.A large percentage of electronic commerce is conducted entirely electronically for virtual itemssuch as access to premium content on a website, but most electronic commerce involves thetransportation of physical items in some way. Online retailers are sometimes known as e-tailersand online retail is sometimes known as e-tail. Almost all big retailers have electronic commercepresence on the World Wide Web.Electronic commerce that is conducted between businesses is referred to as business-to-business orB2B. B2B can be open to all interested parties (e.g. commodity exchange) or limited to specific, pre-qualified participants (private electronic market). Electronic commerce that is conducted betweenbusinesses and consumers, on the other hand, is referred to as business-to-consumer or B2C. Thisis the type of electronic commerce conducted by companies such as Amazon.com.Electronic commerce is generally considered to be the sales aspect of e-business. It also consists ofthe exchange of data to facilitate the financing and payment aspects of the business transactions.Early developmentThe meaning of electronic commerce has changed over the last 30 years. Originally, electroniccommerce meant the facilitation of commercial transactions electronically, using technology suchas Electronic Data Interchange (EDI) and Electronic Funds Transfer (EFT). These were bothintroduced in the late 1970s, allowing businesses to send commercial documents like purchaseorders or invoices electronically. The growth and acceptance of credit cards, automated tellermachines (ATM) and telephone banking in the 1980s were also forms of electronic commerce.Another form of e-commerce was the airline reservation system typified by Sabre in the USA andTravicom in the UK.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 6
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHOnline shopping is an important component of electronic commerce. From the 1990s onwards,electronic commerce would additionally include enterprise resource planning systems (ERP), datamining and data warehousing.An early example of many-to-many electronic commerce in physical goods was the BostonComputer Exchange, a marketplace for used computers launched in 1982. An early onlineinformation marketplace, including online consulting, was the American Information Exchange,another pre Internet online system introduced in 1991.In 1990 Tim Berners-Lee invented the WorldWideWeb web browser and transformed an academictelecommunication network into a worldwide everyman everyday communication system calledinternet/www. Commercial enterprise on the Internet was strictly prohibited until 1991 .[1]Although the Internet became popular worldwide around 1994 when the first internet onlineshopping started, it took about five years to introduce security protocols and DSL allowingcontinual connection to the Internet. By the end of 2000, many European and American businesscompanies offered their services through the World Wide Web. Since then people began toassociate a word "ecommerce" with the ability of purchasing various goods through the Internetusing secure protocols and electronic payment services.Timeline • 1982: Minitel was introduced nationwide in France by France Telecom and used for online ordering. • 1987: Swreg begins to provide software and shareware authors means to sell their products online through an electronic Merchant account. • 1990: Tim Berners-Lee writes the first web browser, WorldWideWeb, using a NeXT computer. • 1992: J.H. Snider and Terra Ziporyn publish Future Shop: How New Technologies Will Change the Way We Shop and What We Buy. St. Martins Press. ISBN 0312063598.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 7
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • 1994: Netscape releases the Navigator browser in October under the code name Mozilla. Pizza Hut offers pizza ordering on its Web page. The first online bank opens. Attempts to offer flower delivery and magazine subscriptions online. Adult materials also become commercially available, as do cars and bikes. Netscape 1.0 is introduced in late 1994 SSL encryption that made transactions secure. • 1995: Jeff Bezos launches Amazon.com and the first commercial-free 24 hour, internet-only radio stations, Radio HK and NetRadio start broadcasting. Dell and Cisco begin to aggressively use Internet for commercial transactions. eBay is founded by computer programmer Pierre Omidyar as AuctionWeb. • 1998: Electronic postal stamps can be purchased and downloaded for printing from the Web. • 1999: Business.com sold for US $7.5 million to eCompanies, which was purchased in 1997 for US $149,000. The peer-to-peer filesharing software Napster launches. ATG Stores launches to sell decorative items for the home online. • 2000: The dot-com bust. • 2002: eBay acquires PayPal for $1.5 billion [2] . Niche retail companies CSN Stores and NetShops are founded with the concept of selling products through several targeted domains, rather than a central portal. • 2003: Amazon.com posts first yearly profit. • 2007: Business.com acquired by R.H. Donnelley for $345 million[3]. • 2008: US eCommerce and Online Retail sales projected to have reached $204 billion, an increase of 17 percent over 2007[4].Business applicationsSome common applications related to electronic commerce are the following: • Email • Enterprise content management • Instant messaging • NewsgroupsVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 8
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • Online shopping and order tracking • Online banking • Online office suites • Domestic and international payment systems • Shopping cart software • Teleconferencing • Electronic ticketsFormsContemporary electronic commerce involves everything from ordering "digital" content forimmediate online consumption, to ordering conventional goods and services, to "meta" services tofacilitate other types of electronic commerce. On the consumer level, electronic commerce is mostly conducted on the World WideWeb. An individual can go online to purchase anything from books or groceries, to expensiveitems like real estate. Another example would be online banking, i.e. online bill payments, buyingstocks, transferring funds from one account to another, and initiating wire payment to anothercountry. All of these activities can be done with a few strokes of the keyboard.On the institutional level, big corporations and financial institutions use the internet to exchangefinancial data to facilitate domestic and international business. Data integrity and security are veryhot and pressing issues for electronic commerce today.Example applicationsE-mail Electronic mail, most commonly abbreviated email and e-mail, is a method of exchangingdigital messages. E-mail systems are based on a store-and-forward model in which e-mailcomputer server systems accept, forward, deliver and store messages on behalf of users, who onlyneed to connect to the e-mail infrastructure, typically an e-mail server, with a network-enableddevice for the duration of message submission or retrieval. Originally, e-mail was alwaysVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 9
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHtransmitted directly from one users device to anothers; nowadays this is rarely the case.An electronic mail message consists of two components, the message header, and the message body,which is the emails content. The message header contains control information, including,minimally, an originators email address and one or more recipient addresses. Usually additionalinformation is added, such as a subject header field. Originally a text-only communications medium, email was extended to carry multi-media content attachments, which were standardized in with RFC 2045 through RFC 2049,collectively called, Multipurpose Internet Mail Extensions (MIME).The foundation for todays global Internet e-mail service was created in the early ARPANET andstandards for encoding of messages were proposed as early as 1973 (RFC 561). An e-mail sent inthe early 1970s looked very similar to one sent on the Internet today. Conversion from theARPANET to the Internet in the early 1980s produced the core of the current service.Network-based email was initially exchanged on the ARPANET in extensions to the File TransferProtocol (FTP), but is today carried by the Simple Mail Transfer Protocol (SMTP), first publishedas Internet standard 10 (RFC 821) in 1982. In the process of transporting e-mail messages betweensystems, SMTP communicates delivery parameters using a message envelope separately from themessage (header and body) itself. Operation overview The diagram to the right shows a typical sequence ofevent that takes place when Alice composes a message using her mail useragent (MUA) She enters the e-mail address of herVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 10
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHcorrespondent, and hits the "send" button. 1. Here MUA formats the message in e-mail format and uses the Simple Mail Transfer Protocol (SMTP) to send the message to the local mail transfer agent (MTA), in this case smtp.a.org, run by Alices Internet Service Provider (ISP). 2. The MTA looks at the destination address provided in the SMTP protocol (not from the message header), in this case bob@b.org. An Internet e-mail address is a string of the form localpart@exampledomain. The part before the @ sign is the local part of the address, often the username of the recipient, and the part after the @ sign is a domain name or a fully qualified domain name. The MTA resolves a domain name to determine the fully qualified domain name of the mail exchange server in the Domain Name System (DNS). 3. The DNS server for the b.org domain, ns.b.org, responds with any MX records listing the mail exchange servers for that domain, in this case mx.b.org, a server run by Bobs ISP. 4. smtp.a.org sends the message to mx.b.org using SMTP, which delivers it to the mailbox of the user bob.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 11
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 5. Bob presses the "get mail" button in his MUA, which picks up the message using the Post Office Protocol (POP3).That sequence of events applies to the majority of e-mail users. However, there are manyalternative possibilities and complications to the e-mail system: • Alice or Bob may use a client connected to a corporate e-mail system, such as IBM Lotus Notes or Microsoft Exchange. These systems often have their own internal e-mail format and their clients typically communicate with the e-mail server using a vendor-specific, proprietary protocol. The server sends or receives e-mail via the Internet through the products Internet mail gateway which also does any necessary reformatting. If Alice and Bob work for the same company, the entire transaction may happen completely within a single corporate e-mail system. • Alice may not have a MUA on her computer but instead may connect to a webmail service. • Alices computer may run its own MTA, so avoiding the transfer at step 1. • Bob may pick up his e-mail in many ways, for example using the Internet Message Access Protocol, by logging into mx.b.org and reading it directly, or by using a webmail service. • Domains usually have several mail exchange servers so that they can continue to accept mail when the main mail exchange server is not available. • E-mail messages are not secure if e-mail encryption is not used correctly.Many MTAs used to accept messages for any recipient on the Internet and do their best to deliverthem. Such MTAs are called open mail relays. This was very important in the early days of theInternet when network connections were unreliable. If an MTA couldnt reach the destination, itcould at least deliver it to a relay closer to the destination. The relay stood a better chance ofdelivering the message at a later time. However, this mechanism proved to be exploitable bypeople sending unsolicited bulk e-mail and as a consequence very few modern MTAs are openmail relays, and many MTAs dont accept messages from open mail relays because such messagesare very likely to be spam.Message formatVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 12
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH The Internet e-mail message format is defined in RFC 5322 and a series of RFCs, RFC 2045through RFC 2049, collectively called, Multipurpose Internet Mail Extensions, or MIME. Although asof July 13, 2005, RFC 2822 is technically a proposed IETF standard and the MIME RFCs are draftIETF standards,[23] these documents are the standards for the format of Internet e-mail. Prior to theintroduction of RFC 2822 in 2001, the format described by RFC 822 was the standard for Internete-mail for nearly 20 years; it is still the official IETF standard. The IETF reserved the numbers 5321and 5322 for the updated versions of RFC 2821 (SMTP) and RFC 2822, as it previously did withRFC 821 and RFC 822, honoring the extreme importance of these two RFCs. RFC 822 waspublished in 1982 and based on the earlier RFC 733 .Internet e-mail messages consist of two major sections: • Header — Structured into fields such as summary, sender, receiver, and other information about the e-mail. • Body — The message itself as unstructured text; sometimes containing a signature block at the end. This is exactly the same as the body of a regular letter.The header is separated from the body by a blank line.Message header Each message has exactly one header, which is structured into fields. Each field has a nameand a value. RFC 5322 specifies the precise syntax.Informally, each line of text in the header that begins with a printable character begins a separatefield. The field name starts in the first character of the line and ends before the separator character":". The separator is then followed by the field value (the "body" of the field). The value iscontinued onto subsequent lines if those lines have a space or tab as their first character. Fieldnames and values are restricted to 7-bit ASCII characters. Non-ASCII values may be representedVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 13
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHusing MIME encoded words.Header fieldsThe message header should include at least the following fields: • From: The e-mail address, and optionally the name of the author(s). In many e-mail clients not changeable except through changing account settings. • To: The e-mail address(es), and optionally name(s) of the messages recipient(s). Indicates primary recipients (multiple allowed), for secondary recipients see Cc: and Bcc: below. • Subject: A brief summary of the topic of the message. Certain abbreviations are commonly used in the subject, including "RE:" and "FW:" Date: The local time and date when the message was written. Like the From: field, many email clients fill this in automatically when sending. The recipients client may then display the time in the format and time zone local to her. • Message-ID: Also an automatically generated field; used to prevent multiple delivery and for reference in In-Reply-To: (see below).Note that the To: field is not necessarily related to the addresses to which the message is delivered.The actual delivery list is supplied separately to the transport protocol, SMTP, which may or maynot originally have been extracted from the header content. The "To:" field is similar to theaddressing at the top of a conventional letter which is delivered according to the address on theouter envelope. Also note that the "From:" field does not have to be the real sender of the e-mailmessage. One reason is that it is very easy to fake the "From:" field and let a message seem to befrom any mail address. It is possible to digitally sign e-mail, which is much harder to fake, butsuch signatures require extra programming and often external programs to verify. Some Internetservice providers do not relay e-mail claiming to come from a domain not hosted by them, butvery few (if any) check to make sure that the person or even e-mail address named in the "From:"field is the one associated with the connection. Some Internet service providers apply e-mailauthentication systems to e-mail being sent through their MTA to allow other MTAs to detectforged spam that might appear to come from them.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 14
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHRFC 3864 describes registration procedures for message header fields at the IANA; it provides forpermanent and provisional message header field names, including also fields defined for MIME,netnews, and http, and referencing relevant RFCs. Common header fields for email include: • Bcc: Blind Carbon Copy; addresses added to the SMTP delivery list but not (usually) listed in the message data, remaining invisible to other recipients. • Cc: Carbon copy; Many e-mail clients will mark e-mail in your inbox differently depending on whether you are in the To: or Cc: list. • Content-Type: Information about how the message is to be displayed, usually a MIME type. • In-Reply-To: Message-ID of the message that this is a reply to. Used to link related messages together. • Precedence: commonly with values "bulk", "junk", or "list"; used to indicate that automated "vacation" or "out of office" responses should not be returned for this mail, eg. to prevent vacation notices from being sent to all other subscribers of a mailinglist. • Received: Tracking information generated by mail servers that have previously handled a message, in reverse order (last handler first). • References: Message-ID of the message that this is a reply to, and the message-id of the message the previous was reply a reply to, etc. • Reply-To: Address that should be used to reply to the message. • Sender: Address of the actual sender acting on behalf of the author listed in the From: field (secretary, list manager, etc.).Content encodingE-mail was originally designed for 7-bit ASCII. Much e-mail software is 8-bit clean but mustassume it will communicate with 8-bit servers and mail readers. The MIME standard introducedcharacter set specifiers and two content transfer encodings to enable transmission of non-ASCIIdata: quoted printable for mostly 7 bit content with a few characters outside that range and base64for arbitrary binary data. The 8BITMIME extension was introduced to allow transmission of mailwithout the need for these encodings but many mail transport agents still do not support it fully.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 15
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHIn some countries, several encoding schemes coexist; as the result, by default, the message in anon-Latin alphabet language appears in non-readable form (the only exception is coincidence,when the sender and receiver use the same encoding scheme). Therefore, for internationalcharacter sets, Unicode is growing in popularity.Plain text and HTML Most modern graphic e-mail clients allow the use of either plain text or HTML for themessage body at the option of the user. HTML e-mail messages often include an automatically-generated plain text copy as well, for compatibility reasons. Advantages of HTML include the ability to include inline links and images, set apartprevious messages in block quotes, wrap naturally on any display, use emphasis such asunderlines and italics, and change font styles. Disadvantages include the increased size of theemail, privacy concerns about web bugs, abuse of HTML email as a vector for phishing attacksand the spread of malicious software. Mailing lists commonly insist that all posts to be made in plain-text [27][28][29] for all theabove reasons, but also because they have a significant number of readers using text-based e-mailclients such as Mutt. Some Microsoft e-mail clients have allowed richer formatting by using RTF rather thanHTML, but unless the recipient is guaranteed to have a compatible e-mail client this should beavoided.Servers and client applicationsVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 16
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHThe interface of an e-mail client, Thunderbird. Messages are exchanged between hosts using the Simple Mail Transfer Protocol withsoftware programs called mail transfer agents. Users can retrieve their messages from serversusing standard protocols such as POP or IMAP, or, as is more likely in a large corporateenvironment, with a proprietary protocol specific to Lotus Notes or Microsoft Exchange Servers.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 17
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHWebmail interfaces allow users to access their mail with any standard web browser, from anycomputer, rather than relying on an e-mail client. Mail can be stored on the client, on the server side, or in both places. Standard formats formailboxes include Maildir and mbox. Several prominent e-mail clients use their own proprietaryformat and require conversion software to transfer e-mail between them. Accepting a message obliges an MTA to deliver it, and when a message cannot bedelivered, that MTA must send a bounce message back to the sender, indicating the problem.Filename extensions Upon reception of e-mail messages, e-mail client applications save message in operatingsystem files in the filesystem. Some clients save individual messages as separate files, while othersuse various database formats, often proprietary, for collective storage. A historical standard ofstorage is the mbox format. The specific format used is often indicated by special filenameextensions:eml Used by many e-mail clients including Microsoft Outlook Express, Windows Mail and Mozilla Thunderbird.[31] The files are plain text in MIME format, containing the e-mail header as well as the message contents and attachments in one or more of several formats.emlx Used by Apple Mail.msg Used by Microsoft Office Outlook.mbx Used by Opera Mail, KMail, and Apple Mail based on the mbox format.Some applications (like Apple Mail) also encode attachments into messages for searching whilealso producing a physical copy of the files on a disk. Others separate attachments from messagesby depositing them into designated folders on disk.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 18
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHURI scheme mailto:The URI scheme, as registered with the IANA, defines the mailto: scheme for SMTP emailaddresses. Though its use is not strictly defined, URLs of this form are intended to be used to openthe new message window of the users mail client when the URL is activated, with the address asdefined by the URL in the To: field. [TeleconferenceA teleconference or teleseminar is the live exchange and mass articulation of information amongseveral persons and machines remote from one another but linked by a telecommunicationssystem. Terms such as audio conferencing, telephone conferencing and phone conferencing arealso sometimes used to refer to teleconferencing.The telecommunications system may support the teleconference by providing one or more of thefollowing audio, video, and/or data services by one or more means, such as telephone, computer,telegraph, teletype, radio, and television.Internet tele conferencingInternet teleconferencing includes internet telephone conferencing, videoconferencing, andAugmented Reality conferencing.Internet telephony involves conducting a teleconference over the Internet or a Wide AreaNetwork. One key technology in this area is Voice over Internet Protocol (VOIP). Popular softwarefor personal use includes Skype, Google Talk, Windows Live Messenger and Yahoo Messenger. A working example of a Augmented Reality conferencing was demonstrated at the Salonedi Mobile in Milano by AR+RFID Lab TELEPORT is another AR teleconferencing tool.Electronic ticket E-ticket" redirects here. For the former Disneyland and Disney World tickets, see E ticket.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 19
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH An electronic ticket or e-ticket is used to represent the purchase of a seat on a passengerairline, usually through a website or by telephone. This form of airline ticket has rapidly replacedthe old multi-layered paper tickets (from close to zero to 100% in about 10 years) and becamemandatory for IATA members as of June 1, 2008. During the last few years, where paper ticketswere still available, airlines frequently charged extra for issuing them. E-tickets are also availablefor certain entertainment venues. Once a reservation is made, an e-ticket exists only as a digital record in the airlinecomputers. Customers usually print out a copy of their receipt which contains the record locatoror reservation number and the e-ticket number. According to critical acclaim, Joel R. Goheen is recognized as the Inventor of ElectronicTicketing in the Airline Industry, an industry where global electronic ticket sales (the industrystandard) accounts for over $400 Billion (US) a year (2007). See Patents for Electronic TicketingInventions in the Airline Industry.Electronic tickets have been introduced in road, urban or rail public transport as well.Checking in with an e-ticketTo check in with an e-ticket, the passenger usually comes to the check-in counter and presents thee-ticket itinerary receipt which contains a confirmation or reservation code. In some airports andairlines its not even necessary to present this document or quote the confirmation code or e-ticketnumber as the reservation is confirmed solely on the basis of the passengers identity, which maybe proven by a passport or the matching credit card. Other than that the rest of the check-inprocess remains the same from when paper tickets were still the norm. That is, the passengerchecks-in his/her luggage. It is important to note the the e-ticket is not a substitute for theboarding pass which must still be issued at the end of the check-in process which will usually say"Electronic Ticket" or "E-ticket".VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 20
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHSelf-service and remote check-inE-tickets are very popular because they allow extra services like: • online/telephone/self-service kiosk check-in • early check-in • printing boarding passes at airport kiosks and at locations other than an airport • automated refunds and exchanges online, by telephone and at kiosksSeveral web sites exist to help people holding e-tickets accomplish online check-ins in advance ofthe twenty-four-hour airline restriction. These sites store a passengers flight information and thenwhen the airline opens up for online check-in the data is transferred to the airline and theboarding pass is emailed back to the customer. E-ticket limitationsE-tickets are sometimes not available for some flights from an airline which usually offers them.This can be due to a number of reasons, the most common being software incompatibility. If anairline issues tickets for a codeshare flight with another company, and there is no e-ticketinterlining agreement, the operating carrier would not be able to see the issuing carriers ticket.Therefore, the carrier that books the flight needs to provide hard copy versions of the tickets sothat the ticket can be processed. Similarly, if the destination airport does not have access to theairline who booked the flight, a paper ticket needs to be issued.Industry discount (ID) tickets also tend to be issued on paper if they are valid for more than oneairline, and if the airlines that the tickets are valid for do not have an interlining agreement. Sincee-ticket interlining is still the exception rather than the rule, tickets valid for more than one airlineare usually issued on paper.Currently the ticketing systems of most airlines are only able to produce e-tickets for itineraries ofno more than 16 segments, including surface segments.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 21
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH UNIT – I PART – A1. Define E – Commerce. The act of conducting business on-line, e-commerce may include buying and selling productswith digital cash and via electronic data interchange.2. What are the elements of E – Commerce? • Business - to – Business electronic commerce • Business - to – Consumer electronic commerceVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 22
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • Transaction and business processes that support selling and buying activities on the Internet.3. Define TelecommutingThe Web is helping people work more effectively is by enabling employees of many differentkinds of companies to work at home. In this arrangement is called Telecommuting or Telework.4. Define C2C. It includes individuals who buy and sell items among themselves.5. Define B2G It includes business transaction with government agencies, such as paying taxes and filingrequired reports.6. Define EFT It is electronics transmission of account exchange information over private communicationnetwork.7. Define EDI Electronic Data Interchange (EDI) occurs when one business transmit computer – readabledata in a standard format to another business.8. Define VAN A Value added network is an independent firm that offers connection and transaction –forwarding services to buyers and sellers engaged on EDI.9. Define Commerce Commerce or Doing Business, is a negotiated exchange of valuable objects or servicesbetween at least two parties and includes all activities that each of the parties undertakes tocomplete the transaction10. What are the elements of traditional commerce for buyer’s side? • Identify specific need • Search for products or services that will satisfy the specific need • Select a vendor • Negotiate a purchase transaction, including : Delivery logistics, Inspection, testing, and acceptance.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 23
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • Make payment • Perform regular maintenance and make warranty claims.11. What are the elements of traditional commerce for Seller’s side? • Conduct market research to identify customer needs • Create product or service that will meet customer’s needs • Advertise and promote product or service • Negotiate a purchase transaction, including : Delivery logistics, Inspection, testing, and acceptance. • Ship goods and invoice customer • Receive and process customer payments • Provide after – sale support, maintenance and warranty services.12. Define activity Activity is a task performed by a worker in a course of doing his or her job.13. Define Transaction A transaction is an exchange of value, such as a purchase, a sale, or the conversion of rawmaterials into a finished product.14. Define Business processes The group of logical, related, and sequential activities and transaction in which businessengage are often collectively referred to as business processes.15. Define Commodity A commodity item is a product or service that is hard to distinguish from the sameproducts or services provided by other sellers.16. Give some example of e-commerce • Sale / Purchase of books and CDs. • Online delivery of software. • Sale/ Purchase of travel services. • Online shipment tracking. • Sale/ Purchase of investment and insurance products.17. Give some example of Traditional -commerce • Sale/ Purchase of impulse items for immediate use. • Sale/ Purchase of perishable food products.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 24
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • Small – denomination purchases and sales. • Sale/ Purchase of high – value jewelry and antiques.18. What are the advantages of e – commerce? All the advantages of electronics commerce for business can be summarized in one statement:Electronic commerce can increase sales and decrease costs.19. What are the disadvantages of e – commerce? Some business processes may never land themselves to electronics commerce. For example,perishable foods and high – cost, unique items, such as custom – designed jewelry and antiques,may be impossible to inspect adequately from a remote location, regardless of any technologiesthat might be devised in the future. Most of the disadvantages of electronic commerce today,however stem from newness and rapidly developing pace of the underlying technologies.20. Define Transaction cost. Transaction costs are the total of all that a buyer and seller incur as they gather informationand negotiate a purchase – sale transaction.21. Define Vertical Integration. The practice of an existing firm replace one or more of its supplier markets with its ownhierarchical structure for creating the supplied product is called vertical Integration.22. Define Strategic alliances Network economic structure, companies coordinate their strategies, resources, and skill setsby forming long – term, stable relationships with other companies and individuals based onshared purpose. These relationships are often called strategic alliances or strategic partnership.23. Define Law of diminishing returns. Economists have found that most activities yield less value as the amount of consumptionincreases. This characteristic of economic activity is called the law of diminishing returns.24. Define Network effect. An interesting exception to the law of diminishing returns occurs as more people ororganizations participate in a network, the value of the network to each participant increase. Theincrease in value is called the network effect.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 25
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH25. Define Business Unit. A strategic business unit, or simply business unit, is one particular combination of product,distribution channel, and customer type.26. Define value chain A value chain is a way of organizing the activities that each strategic business unitundertakes to design, produce, promote, market, deliver, and support the products or services itsells.27. What is meant by SWOT Analysis? The acronym is short for strengths, weaknesses, opportunities and threats.28. Write the result for the SWOT analysis? • Strengths – Sell directly to consumers, Keep costs below competitors costs. • Weaknesses – No strong relationships with computer retailers. • Opportunities – Consumer desire for one – stop shopping, Consumers know what they want to buy, Internet could be a powerful marketing tool. • Threats – Competitors have stronger brand names, Competitors have strong relations with computer retailers.29. Define Computer Networks A computer network is any technology that allows people to connect computers to each other.30. Define Internet. The Internet is a large system of interconnected computer networks than spans the globe.31. Define mailing list. A mailing list is an e – mail address that forwards any message it receives to any user whohas subscribed to that list.32. Define Hypertext server. A hypertext server is a computer that stores files written in the hypertext markup languagesand lets other computers connect to it and read these files.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 26
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH33. Define Web server. A hypertext server is a computer that stores files written in the hypertext markup languagesand lets other computers connect to it and read these files. Hypertext server used on the webtoday are usually called Web server.34. Define Web browser. A web browser is a software interface that lets users read HTML documents and move fromone HTML format to another through text formatted with hypertext link tags in each file.35. Define Hypertext. System in which text on one page links to text on other pages. This is called Hypertext.36. Define GUI. A Graphical user interface is a way of presenting program control functions and programoutput to users. It uses pictures, icons, and other graphical elements instead of displaying just text.37. Define Hyperlink. A hypertext link, or hyperlink, points to another location in the same or another HTMLdocument. It is an important type of tag.38. Define WWW. WWW or Web is a subset of the computers on the Internet that are connected to each other ina specific way that makes them and their contents easily accessible to each other.39. Write the abbreviation for the following termsNAP – Network Access PointISP – Internet Service ProvidersNSF – National Science Foundation40. Write the abbreviation for the following terms • EDI – Electronic data interchange. • EFT – Electronic funds transfer. • C2C – Consumer- to- consumer • B2B – Business- to- business. • B2G – Business- to – government.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 27
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • B2C – Business – to – consumer. UNIT – II PART – A1. Define LAN. A network of computers that are located close together is called a local area network(LAN).2. Define WAN Networks of computers that are connected over greater distances are called wide areanetworks(WAN)3. Define MAN. A man is not generally owned by a signle organization. The Man, its communication linksand equipment are generally owned by either a consortium of users or by a single networkprovides who sells the service to the users.4. Define Circuit switching This circuit forms a single electrical path between caller and receiver. This single path ofconnected circuits switched into each other is maintained for the entire length of the call. This typeof centrally controlled, single connection model is known as circuit switching.5. Define Circuit . The combination of telephone lines and the closed switches that connect them to each other iscalled a circuit.6. Define Packet switching. Any message exceeding a network defines maximum length is broken up into shorter units,known as packets, for transmission; the packets, each with an associated header, are thetransmitted individually through the network.7. Define Message switching. This is the store and forward the message. Sometimes there is no need for a circuit to beestablished all the way from source to the destination. Consider a connection between the users (Aand B). the connection represented by a series of link (AB, BC and CD).VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 28
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHThe message is stored at B and then forwarded.8. Define Router. A device that forwards data packets along networks. A router is connected to at least twonetworks, commonly two LANOR WANS or a LAN and is ISPs network. It located at gate ways.9. Define Routing algorithm. The programs on router computers that determine the best path on which to send each packetcontains rules called routing algorithms.10. Define Gateways. A gateway is a network point that acts asan entrance to another network. On the Internet,anode or stopping point canbe either a gateway node or a host node.11. Define Protocol. A protocol is a collection of rules for formatting, ordering, and error-Checking data sent acrossa network.12. Define Backbone routers. The routers are very large computers that can each handle more than 50 million packets persecond! These routers are sometimes called backbone routers.13. What are the main protocol used in Internet?Transmission control protocol(TCP)Internet protocol(IP)14. Define IP Address. It uses a 32 nit number to identify the computers connected to the Internet. This address iscalled an IP address.15. Write the abbreviation for the following terms • TCP/IP – Transmission Control Protocol / Internet protocol. • IPV4 – Internet Protocol Version 4.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 29
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH • IPV6 – Internet Protocol Version 6. • ARIN – American registry for Internet Numbers. • RIPE – Reseaux IP Europeans. • APNIC – Asia – Pacific Network Information Center. • IANA Internet Assigned Numbers Authority.– • IEFT – Internet Engineering Task Force.16. Define Domain names. Domain names are sets of words that are assigned to specific IP addresses. Domain names cancontain two or more words groups separated by periods.17. Define Web client. Web client software or web browser software.18. Define Web server. Web client software sends requests for web page files to other computers web server19. Define E – mail. E-mail that is sent across the Internet must also be formatted according to a common set ofrules.20. Write the abbreviation for the following termsSMTP – Simple Mail Transfer ProtocolPOP – Post Office ProtocolMIME – Multipurpose Internet mail Extensions21. Define tags. A text markup language specifies a set of tags that are inserted into the text. These markuptags, also called tags.22. Define SGML. The markup language most commonly used on the web is HTML, which is a subset of a mucholder and far more complex text markup language called Standard Generalized Markup Language(SGML)23. Define XML.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 30
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH A markup language that was derived from SGML for use on the web is Extensible markuplanguage( XML),24. Define W3C. The World Wide Web consortium(W3C), a not-for-profit group that maintains standards forthe web, presented its first draft from of XML in 1996.25. Define XHTML. In 2000, the W3C released the first version of a recommendation for a new markup languagecalled Extensible Hypertext Markup Language(XTML).26. Define Markup languages and what are the elements for the Hypertext? The text elements that are related to each other are called hypertext elements.27. Define Homepage. In a hierarchical hyperlink structure, the web user opens an introductory page called a homepage or start page..28. Define CSS. Cascading style sheets(CSS) are sets of instructions that give web developers more controlover the format of displayed pages.29. Define Internets. The Internet is a large system of interconnected computer networks than spans the globe.30. Define Intranets. Corporate networks that house internal memos, corporate policy handbooks, expense accountworksheets, budgets, newsletters and a variety of other corporate documents31. Define Extranets. Intranets that allow certain authorized parties outside the company to access certain parts ofthe information stored in the system32. Define Private networks.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 31
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH The private network is a private, leased-line connection between two companies thatphysically connects their intranets to one another.33. Define Leased line. A leased line is a permanent telephone connection between two points.34. Define VPN. A virtual private network (VPN) is an extranet that uses public networks and theirprotocols to send sensitive data to partners, customers, suppliers, and employees using a systemcalled IP tunneling or encapsulation.35. Define Encapsulation. The passageway is created by VPN software that encrypts the packet content and then placesthe encrypted packets inside another packet in a process called encapsulation.36. Define IP Wrapper. The passageway is created by VPN software that encrypts the packet content and then placesthe encrypted packets inside another packet in a process called encapsulation. The outer packet iscalled an IP Wrapper.37. What is mean by Internet access provider? Larger firms that provide Internet access to other businesses, called Internet access providers(IAPs). Information that can travel from the Internet to a user in a given amount of time.38. Define bandwidth. Bandwidth is the amount of data that can travel through a communication line per unit oftime.39. Define Net bandwidth. Traffic on the Internet and at your local service provider greatly affects net bandwidth40. Define Symmetric connections. Symmetric connections provide the same bandwidth in both directions.41. Define Asymmetric connections.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 32
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH Asymmetric connections provide different bandwidths for each direction.42. Define upstream band width. Upstream bandwidth, also called upload bandwidth, is a measure of the amount ofinformation that can travel from the user to the Internet in a given amount of time.44. What is mean by broad band services? Connections that operate at speeds of greater than about 200 Kbps are called broadbandservices.45. Define high speed DSL. Connection services is available on there provides 768Kbps of symmetric bandwidth iscalled as high speed DSL46. Define WAP A wireless access point (WAP) is a device that transmits network packets between WI-Fiequipped computers and other devices that are within its range.47. Define PAN. These small Bluetooth networks are called personal area networks (PANs) UNIT – III PART - A1. What are the elements for the Web server? • Hardware • Operating system software • Web server software2. What are the different sites of Web sites? • Development site • Extranet • Intranet • Transaction processing sites • Content delivery sitesVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 33
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH3. Define Development sites. Simple sites that companies use to evaluate different web designs with little initial investment.A development site can reside on an existing PC running web server software. Multiple testersaccess the site through their client computers on an existing LAN.4. Define Transaction – processing sites. Commerce sites such as business-to-business and business-to-consumer electronic commercesites that must be available 24 hours a day, seven days a week.5. Define Content – delivery sites. Sites that deliver content such as news, histories, summaries, and other digital information.Visitors must be able to locate articles quickly with a fast and precise search engine.6. Define Dynamic page. A dynamic page is a web page whose content is shaped by a program in response to userequests.7. Define Static page.A static page is an unchanging page retrieved from disk.8. Define Dynamic content. Dynamic content is nonstatic information constructed in response to a web clients request.9. What is mean by server side scripting? In server-side scripting, programs running on the web server create the web pages beforesending them back to the requesting web clients as parts of response messages.10. Define Server software. The software that the server computer uses to make these files and programs available to theother computers is sometime called server software.11. Define Database Software. The server computer on which database management software runs is often called a databaseserver.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 34
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH12. What is mean by request message? The message that a web client sends to request a file or files from a web server is called arequest message.13. What is mean by response message? The server does this by retrieving the web page file from its disk and then creating a properlyformatted response message.14. Define response header line. The response header line indicates the HTTP version used by the server, the status of theresponse and an explanation of the status information.15. Define response header field. A response header field returns information describing the server’s attributes. The entity bodyreturns information describing the server’s attributes.16. What is mean by 3 – tier architecture? A three-tier architecture extends the two-tier architecture to allow additional processing tooccur before the web server responds to the web client’s request.17. What is mean by N – tier architecture? Higher-order architectures –that is , those that have more than three tiers-are usually calledn-tier architectures.18. Define tracert. Tracert (TRACE RouTe) sends data packets to every computer on the path (Internet)between one computer and another computer and clocks the packets’ round-trip times.19. Define Spam. E-mail does have some drawbacks. One significant annoyance is spam. Spam, also known asunsolicited commercial e-mail20. Define Telnet. Telnet is a program that allows users to long on to a computer that is connected to theInternet. mounted frame.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 35
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH21. Define FTP. The File Transfer Protocol (FTP) is the part of the TCP/IP rules that defines the formats usedto transfer files between TCP/IP connected computers.22. What are the types of FTP. • Full privilege FTP • Anonymous FTP23. Define full privilege FTP. An FRP connection to a computer on which the user has an account is called full privilegeFTP.24. Define Anonymous FTP. One way to access a remote computer is called anonymous FTP. It allows the user to log on asa guest.25. What is mean by orphan file.An orphan file is a file on the web site that is not linked to any page.26. Define blade server. A recent innovation in server computer design is to put small server computers on a singlecomputer board and then install many of those boards into a rack- mounted frame. These servers-on-a-cards are called blade servers.27. Define Virtual server. A virtual server or virtual host is a feature that maintains more than one server on onemachine.28. What is mean by Benchmarking? Benchmarking is testing that is used to compare the performance of hardware and software.29. Define Throughput. Throughput is the number of HTTP requests that a particular hardware and softwarecombination can process in a unit of time.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 36
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH30. Define Response time. Response time is the amount of time a server requires to process one request.31. Define Centralized architecture. Centralized architecture is to use a few very large and fast computers.32. Define distributed architecture. If use a large number of less powerful computers and divide the workload among them.This is sometimes called a distributed architecture.33. What are the types of hosting? Self hosting Shared hosting Dedicated hosting34. Define Self – hosting. When companies need to incorporate electronic commerce components, they may opt to runservers in-house; this is called self-hosting.35. Define Shared hosting. Shared hosting means that the client’s web site is on a server that hosts other web sitessimultaneously and is operated by the service provider at its location.36. Define dedicated hosting Dedicated hosting, the service provider makes a web server available to the client, but theclient does not share the server with other clients of the service provider .37. What is mean by scaleable? Best hosting services provide web server hardware and software combination that arescalable, which means that they can be adapted to meet changing requirements when their clientsgrow.38. What is mean by middle ware? Larger companies usually establish the connections between their electronic commercesoftware and their existing accounting system by using a type of software called middleware.39. Define application server.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 37
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH An application server is a computer that takes the request messages received by the webserver and runs application programs that perform some kind of action based on the contents ofthe request messages.40. Define database manager. A database manager is software that stores information in a highly structured way.41. What are the rules for the business logic? The actions that the application server software performs are determined by the rules used inthe business. These rules are called business logic.42. Define Distributed information systems. Large information systems that store the same data in many different physical location arecalled distributed information systems43. Define Distributed database systems. Large information systems that store the same data in many different physical location arecalled distributed information systems The databases within those systems are called distributeddatabase systems.44. Define SOAP. The Simple Object Access Protocol (SOAP) is a message-passing protocol that defines how tosend marked up data from one software application to another across a network.45. Define ERP. Enterprise resource planning (ERP) software packages are business systems that integrate allfacets of a business, including accounting, logistics, manufacturing, marketing, planning, projectmanagement and treasury functions.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 38
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH UNIT – IV PART - A1. What are the classifieds for the computer security? * Secrecy * Integrity * Availability * Key management * Nonrepudiation * Authentication2. Define secrecy? Secrecy refers to protecting against unauthorized data disclosure and ensuring theauthenticity of data source3. Define integrity? Integrity refers to preventing unauthorized data modification4. Define necessity? Necessity refers to preventing data delays or denials5. Define security policy? A security policy is a written statement describing which assets to protect and why are theyprotected and who are responsible for that protection and what behaviors are acceptable6. What are the elements for the security policy? * Authentication * Access control * Secrecy * Data integrity * AuditVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 39
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH7. What is meant by Cyber squatting? Cyber squatting is the practice of registering a domain name that is trade mark of anotherperson in hope that the owner will pay huge amount to acquire the URL.8. Define Java script? Java script is a scripting language that is developed by Netscape to enable Web pagedevelopers to build active amount.9. Define virus? A virus is software that attaches itself to another program and cause damage when hostprogram is activated.10. Define worm? A worm is a type of virus that replicates itself on the computer it infects and it can spreadquickly through INTERNET.11. Define macro virus? A micro virus is a type of virus that is coded as small program called macro and is embeddedin a file.12. Define Domain Name Server? Domain name servers are the computers on internet that maintains directories that linkdomain name to IP address.13. Define spoofing? Masquerading or spoofing – pretending to be someone you are not ,or representing a websiteas an original when it is fake – is one means of distributing web sites.14. What is the purpose of necessity threats? The purpose of a necessity threat, also known as by other names such as a delay, denial, ordenial – of – service threat (DoS), is to disrupt normal computer processing, or deny processingentirely.15. What is meant by buffer? A buffer is an area of memory set aside to hold data read from a file or database. A buffer isnecessary whenever any input or output operation takes place because a computer can process fileVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 40
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHinformation much faster than the information can be read from input devices or written to outputdevices. A buffer serves as a holding area for incoming or outgoing data.16. What is meant by Availability? Provide delivery assurance for each message segment so that message or message segmentscannot be lost undetectably.17. What is meant by key management? Provide secure distribution and management of keys needed to provide securecommunications.18. What is meant by Non-repudiation? Provide undeniable, end – to – end proof of each message’s origin and recipient.19. What is meant by Authentication? Securely identify clients and server with digital signatures and certificates.20. What is meant by copy control? Copy control is an electronic mechanism for limiting number of copies that one can make ofa digital work.21. Define Digital certificate? A digital certificate, also known as a digital ID, is an attachment to an e – mail message or aprogram embedded in a web page that verifies that the sender or web site is who or what it claimsto be. In addition, the digital certificate contains a means to send an encrypted message – encodedso others cannot read it – to the entity that sent the original web page or e – mail message.22. What are the elements for the digital certificate?(i).Certificate owner’s identifying information, such as name, organization, address, and so on.(ii)Certificate owner’s public key.(iii)Dates between which the certificate is valid.(iv)Serial number of the certificate.(v)Name of the certificate issuer(vi)Digital signature of the certificate issuer.23. What are the options for the security setting level?Security level options are Low, Medium – Low, Low, High.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 41
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH24. Define Encryption? Encryption is the coding of information by using a mathematically based program and asecret key to produce a string of characters that is unintelligible.25. Define Cryptography? Cryptography is the science of creating message that only the sender and receiver can read.Cryptography does not hide text; it converts it to other text that is visible, but does not appear tohave any meaning.26. Define Encryption program? The program that transforms normal text, called clear text into cipher text (theunintelligible string of characters) is called encryption program.27. What are the function for Encryption? (i)Hash Coding (ii)Asymmetric encryption (public key encryption) (iii) Symmetric encryption.28. Define Hash coding? Hash coding is a process that uses a hash algorithm to calculate a number, called a hashvalue, from a message of any length. It is a fingerprint for the message because it is almost certainto be unique for each message.29. Define Asymmetric Encryption? Asymmetric encryption, or public – key encryption, encodes messages by using twomathematically related numeric keys. In their system, one key of the pair, called public key, isfreely distributed to the public at large - to anyone interested in communicating securely with theholder of both keys.30. Define Symmetric Encryption? Symmetric encryption also known as private – key encryption, encodes a message by usinga single numeric key, such as 456839420783, to encode and decode data. Because the same key isused, both the message sender and the message receiver must know the key. Encoding anddecoding message using symmetric encryption is very fast and efficient.31. How is public key encryption advantageous over private key encryption?VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 42
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH Public key systems provide several advantages over private key encryption methods. First,the combination of key required to provide private message between enormous numbers ofpeople is small. Second, key distribution is not a problem. Each person’s public key can be postedanywhere and does not require any special handling to distribute. Third, public key systems makeimplementation of digital signatures possible.32. Define Firewall? A firewall is a computer and software combination that is installed at the Internet entrypoint of a networked system.33. What are the characteristics of firewalls?(i)All traffic from inside to outside and from outside to inside the network must pass through it.(ii)Only authorized traffic, as defined by the local security policy, is allowed to pass through it.(iii)The firewall itself is immune to penetration.34. Define Trusted / Untrusted? Those networks inside the firewall are often called trusted, whereas networks outside thefirewall are called untrusted.35. What are the classifieds for the firewalls? (i) Packet – filter firewalls. (ii) Gateway Servers (iii) Proxy Servers.36. Define Packet-filter firewall? Packet – filter firewalls examine all data flowing back and forth between the trustednetwork(within the firewall) and the Internet. Packet filtering examines the source and destinationaddresses and ports of incoming packets and denies or permits entrance to the packets based on apre programmed set of rules.37. Define Gateway server? Gateway server are firewalls that filter traffic based on the application requested. Gatewayserver limit access to specific applications such as Telnet, FTP, and HTTP. A gateway firewallprovides a central point where all requests can be classified, logged, and later analyzed.38. Define proxy server? Proxy servers are firewalls that communicate with the internet on the private network’sVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 43
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHbehalf. When a browser is configured to use a proxy server firewall, the firewall passes thebrowser request to the internet. When the internet sends back a response, the proxy server relaysit back to the browser. Proxy server are also used to serve as a huge cache for web pages.39. Define Integrity Threats? An Integrity threat, also known as active wiretapping, exists when an unauthorized party canalter a message stream of information.40. Define cyber vandalism? Cyber vandalism is the electronic defacing of an existing web site’s page. The electronicequivalent of destroying property or placing graffiti on objects, cyber vandalism occurs wheneversomeone replaces a web site’s regular content with his or her own content.41. What are the types of cookies? 1. Session cookies. 2. Persistent cookies.42. Define Session Cookies? Session cookies, which exist until the web client ends the connection(or “session”).43. Define Persistent cookies? Persistent cookies, which remain on the client computer indefinitely. Electronic commercesites use both kinds of cookies.44. Define Ethical Hacking? Ethical hackers, these computer sleuths are hired to probe PCs and locate information that canbe used in legal proceedings.45. Define computer forensics? The field of computer forensics is responsible for the collection, preservation, and analysis ofcomputer – related evidence.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 44
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH UNIT – V PART - A1. Define Intelligent Agent? An Intelligent agent is software that assists people and acts on their behalf. Intelligentagents work by allowing people to delegate work that they could have done, to the agentsoftware.2. Define Agent? Agents are seen as a way of supplying software that acts as the representative of the user’sgoals in the complex environment. Agent software can provide the glue between the applications,freeing the user from the complexity of dealing with the separate application environments.3. Define Single Agent? A single agent system is one in which the problem domain is encapsulated within thesystem. Single – agent systems are not configured to interface with other agents.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 45
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH4. Define Multi Agent? Multi Agent systems, on the other hand, are much more complex to design and test, butthey provide greater potential for electronic commerce applications since the interaction betweenagents of multiple systems is possible. A multi – agent environment necessitates that cooperationbetween agents exists.5. Why is Agent Technology useful? For a new technology to be considered valuable and useful to the marketplace.6. Write characteristics for the Agent technology?(i)The ability to solve problems that have hitherto been beyond the scope of automation – eitherbecause no existing technology could be used to solve the problem, or because it was consideredtoo expensive.(ii)The ability to solve problems that can already be solved in a significantly better way.7. Write the function of Intelligent Agent? (i) Agency (ii) Intelligence. (iii) Mobility.8. Define Agency? The degree of autonomous action that can be taken; that is actions performed without theneed for direct human intervention or intervention by other agents. The agent have control overthe actions performed within its system, ie., not have actions imposed by other agents. Actions canbe requested by other agents, but the agent itself decides whether to approve and allow the action.9. Define Intelligence? The extend to which an agent understand its own internal state and its externalenvironment. The level of intelligence is further classified according to its ability to respond, toadapt, and to take initiative.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 46
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH10. Define Respond? Agents should “perceive” and “respond” to their environments.11. Define Adapt? Agents should have the ability to detect changes in user’s environment and the relevantenvironment.12. Define Initiate? Agents should be able to determine when new or different “goal – directed behavior isnecessary by first recognizing a developing need to achieve that goal.13. Define Mobility? Agent mobility refers to the ability of software to travel from machine to machine andperform tasks or processes on foreign computers. When necessary, agents should be able tointeract with other agents and humans, both to perform their own activities and to help othersagents and humans with theirs.14. Define Agent society? A system or environment where multiple agents work together to achieve multiple, butinterdependent goals is called an agent society.15. What are the features of Agent society? (i) openness (ii) complexity of society (iii) interfacing techniques (iv) negotiation (v) internal control methods.16. Define openness? Openness of a system refers to the capability of the system to dynamically change in responseto its environment.17. Define complexity of society?VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 47
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH Complexity of society involves the manner in which tasks are decomposed into manageableunits, similar to object orient design.18. Define Interfacing? Interfacing techniques help the various agents in the society to connect and communicate.Autonomous or semi – autonomous agents, or nodes in a society must employ some agreed uponinterfaces.19. Define Negotiation? Negotiation between agents is a key component of societies, and the method used to negotiatecan affect the quality and optimization of decisions made by agents.20. Define Internal controls? Internal controls over the data used by agents and the actual knowledge base contained by theagent are another feature of agent societies.21. What are the technologies used in online information chain? (i)Pull or Pull Technology (ii)Push or Push Technology22. Define continuous reliability assurance? Continuous reliability assurance is the type of assurance service that accountants can performover real – time computer based systems.23. What is an aglet? A Java Knowledge Query and Manipulation Language (JKQML) has been developed andused in mobile agents written in applets, called aglets.24. Define Marketing? Marketing is the process of planning and executing the conception, pricing, promotion, andVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 48
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHdistribution of ideas, goods, and services to create exchanges that satisfy individual andorganizational goals.25. Define Product? A product is a good service that a business offers to its customers. Without some sort of viableproduct to offer, a business cannot survive.26. Define Service product? Service product generally involves the performance of a task for the customer; examplesinclude work performed by doctors, accountants, hairdressers, and actors.27. Define Pricing? The pricing of goods refers to the processes involved in determining the amount to charge fora specific physical good or service. Pricing models are typically used to determine a firm’s price.28. Define Distribution? The distribution task entails moving the product from the producer to the customer. Theproduct may travel directly from the producer to the consumer or it may be channeled throughintermediaries such as wholesalers, warehouses and/or retailers.29. Define One way channels? One – way channels send a message to the potential customer, but do not provide a directmechanism for communication to the business. Eg., radio, roadside bulletin boards, television,magazines, newspapers.30. Define Two way channels? Two- way channels send the message to the potential customer and provide a directmechanism for communication from the potential customer to the business. Eg., direct mail viaphone responses and inquiries, telemarketing web site advertising via forms – based input.31. Write the range of Internet marketing techniques?VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 49
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH The Internet marketing techniques, ranging from passive to aggressive.32. Define Search Engines? Search engines take user – defined strings and Boolean expressions(such as AND and OR) andreturn a list of closely matched web sites in the order of closeness of match.33. Define Banner Advertisements? Typically rectangular in shape, banner advertisements contain text and graphics that areplaced on the screens of search engines, web browser software, and web sites to attract theattention of WWW user.34. Define Click – through Advertisements? The Click – through advertisements, meaning they contain hypertext links to the site aboutwhich the banner is advertising. The banners can contain static text or animation.35. List the four levels of agreement identified by DARPA. (i) Transport (ii) Language (iii) Policy (iv) Architecture36. Define Physical goods? Physical goods generally have a physical, tangible presence and include items such asautomobiles, grocery items, and printed newspapers.37. Define Pull or Pull Technology? Pull or pull technology refers to requesting data from another program or server. The WWWis based on pull technology, where a clients browser must request a web page before it is sent.38. Define Push or Push Technology? Push or push technology refers to sending data to a client without the client requesting it.Information is sent out, regardless of whether anyone is tuned in. PointCast, which deliversVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 50
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHcustomized news to users desktops, is an example of push technology.39. Define router? On the Internet, a router is a device or, in some cases, software in a computer, that directsinformation packets to the next point toward their destination. The router is connected to at leasttwo networks and decides which way to send each information packet based on its currentunderstanding of the state of the networks it is connected to. A router is located at any juncture ofnetworks, including each Internet point-of-presence.40. Define TCP/IP? TCP/IP is the acronym for Transport Control Protocol/Internet Protocol, the suite ofcommunications protocols used to connect hosts on the Internet. TCP/IP uses several protocols,the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is usedby the Internet, making it the de facto standard for transmitting data over networks. Even networkoperating systems that have their own protocols, such as NetWare, also support TCP/IP.41. Define server? A server is a computer on a LAN that provides services or resources to client (stand alone)computers by sharing its resources. Servers may be dedicated, in which case they share theirresources but dont use them themselves, except in performing administrative tasks. Servers mayalso be used to run applications for users, in which case the server is called an application server.Peer-to-peer or workgroup servers, such as servers created by using PCs running Windows NTWorkstation to share disk folders, are another class of server.42. Define work station? A workstation is a client computer (stand alone machine) on a (Local Area Network) or WideArea Network that is used to run applications and is connected to a server from which it obtainsdata shared with other computers. Workstation is also used to describe a high-priced PC that usesa high-performance microprocessor and proprietary architecture to create what some call anVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 51
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH"open" system.43. Define Internet Explorer (IE)? Internet Explorer is Microsofts Web browser. Like Netscape Navigator, Internet Explorerenables you to view Web pages. The major differences between Internet Explorer and Navigatorare: Internet Explorer supports ActiveX and VBScript, while Navigator does not. Internet Explorerruns only under Windows and on Macintoshes whereas Navigator runs on these platforms as wellas UNIX. Otherwise, the two browsers are very similar. Both support Java and JavaScript.44. Define Netscape Communicator? Netscape Communicator is a suite of software components for sharing, accessing, andcommunicating information via intranets and the Internet. Communicator includes componentsfor navigation, (Navigator), email, (Messenger), discussion groups, (Collabra), HTML authoring,(Composer), dynamic information delivery, (Netcaster), real-time collaboration, (Conference),calendar and scheduling, (Calendar), IBM host communications, and Communicatormanagement.45. Define NetWare? A popular local-area network (LAN) operating system developed by Novell Corporation,NetWare is a software product that runs on a variety of different types of LANs, from Ethernet toIBM token-ring networks. It provides users and programmers with a consistent interface that isindependent of the actual hardware used to transmit messages. PART - B1. Write short notes on SGML? The encoding scheme defined by these Guidelines is formulated as an application of asystem known as the Standard Generalized Markup Language (SGML). SGML is an internationalstandard for the definition of device-independent, system-independent methods of representingtexts in electronic form. This chapter presents a brief tutorial guide to its main features, for thosereaders who have not encountered it before. For a more technical account of TEI practice in usingVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 52
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHthe SGML standard, for a more technical description of the subset of SGML used by the TEIencoding scheme, Formal Grammar for the TEI Interchange Format Subset of SGML . SGML is an international standard for the description of marked-up electronic text. Moreexactly, SGML is a metalanguage, that is, a means of formally describing a language, in this case, amarkup language. Before going any further we should define these terms. The word markup has been used to describe annotation or other marks within a textintended to instruct a compositor or typist how a particular passage should be printed or laid out.Examples include wavy underlining to indicate boldface, special symbols for passages to beomitted or printed in a particular font and so forth. As the formatting and printing of texts wasautomated, the term was extended to cover all sorts of special markup codes inserted into electronictexts to govern formatting, printing, or other processing. Generalizing from that sense, we define markup, or (synonymously) encoding, as any meansof making explicit an interpretation of a text. At a banal level, all printed texts are encoded in thissense: punctuation marks, use of capitalization, disposition of letters around the page, even thespaces between words, might be regarded as a kind of markup, the function of which is to helpthe human reader determine where one word ends and another begins, or how to identify grossstructural features such as headings or simple syntactic units such as dependent clauses orsentences. Encoding a text for computer processing is in principle, like transcribing a manuscriptfrom scriptio continua, a process of making explicit what is conjectural or implicit, a process ofdirecting the user as to how the content of the text should be interpreted. By markup language we mean a set of markup conventions used together for encoding texts.A markup language must specify what markup is allowed, what markup is required, how markupis to be distinguished from text, and what the markup means. SGML provides the means for doingthe first three; documentation such as these Guidelines is required for the last. The present chapter attempts to give an informal introduction---much less formal than thestandard itself---to those parts of SGML of which a proper understanding is necessary to makeVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 53
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHbest use of these Guidelines.2. What is electronic commerce used for? Electronic commerce is not limited to certain types of businesses or just technology-relatedproducts and services. Companies in every field are doing business on-line. Networking throughelectronic commerce can be applied to any facet of a companys operations, including marketingand sales; purchasing and logistics; production; design and engineering. The most effective use ofelectronic commerce is when several of these functions are combined: information flows fromsales to purchasing, to production.Electronic commerce can be used to: • Communicate: E-mail and Internet Access • Promote: Businesses are using web pages to advise clients and potential clients about their business and its value. Web pages keep clients informed about products, services, and developments, and they provide the opportunity to answer client questions. They may also use their web sites to solicit market research information from clients or guests who visit their site. Other uses include: • sales -- to sell products, seven days a week, 24 hours per day throughout the globe; product awareness -- online marketing and advertising; customer service -- customer support and communication; economy -- to eliminate some costs of paper transactions and mailing; effectiveness -- due to the speed of communication; it offers the opportunity to work out of the home; to compete globally without setting up offices in other countries; because small companies can compete against much larger companies as no one can tell how large or young your company is based on your Internet presence; to find information, conduct competitive intelligence, or network with other business owners. • Link Internally - Improve communications within your company using an Intranet Intranet: aVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 54
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH private network inside a company or organization. Intranets are used to organize internal company operations, such as payroll and inventory. Externally - Improve communications with suppliers, customers and partners and integrate your business processes using an Extranet. Extranet: connecting of two or more intranets, allowing communication with business partners, suppliers, distributors or customers • Creating New Business Models: Sharing resource with new partners to create virtual global enterprises. The Net has the potential to act as a central nervous system coordinating the business activities of new type of corporate organisms. • set up an arrangement whereby sales information is shared instantaneously with wholesalers, shippers, manufacturers, designers, and even suppliers of raw material.If I dont want to sell electronically, why use electronic commerce? What arethebenefits? You can improve customer service by providing new avenues for promotion and distribution, byresponding more quickly to orders, and by offering more responsive after sales service. You can cut costs and save time by improving the quality of supply chain management, byintegrating back-end production and logistics with front-end marketing and sales, and by lettingthe computer and software do most of the work in controlling inventory. You can cut costs and save time by improving internal functions, by cutting down on meetings,by sharing information, by eliminating endless trails of paper, and by assuring that internalcommunications are precise and understood.3. Write SGML Entities? The aspects of SGML discussed so far are all concerned with the markup of structuralelements within a document. SGML also provides a simple and flexible method of encoding andnaming arbitrary parts of the actual content of a document in a portable way. In SGML the wordVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 55
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHentity has a special sense: it means a named part of a marked up document, irrespective of anystructural considerations. An entity might be a string of characters or a whole file of text. Toinclude it in a document, we use a construction known as an entity reference. For example, thefollowing declaration<!ENTITY tei "Text Encoding Initiative">defines an entity whose name is tei and whose value is the string ``Text Encoding Initiative.This is an instance of an entity declaration, which declares an internal entity. The followingdeclaration, by contrast, declares a system entity:<!ENTITY ChapTwo SYSTEM "sgmlmkup.txt"> This defines a system entity whose name is ChapTwo and whose value is the textassociated with the system identifier --- in this case, the system identifier is the name of anoperating system file and the replacement text of the entity is the contents of the file. Once an entity has been declared, it may be referenced anywhere within a document. Thisis done by supplying its name prefixed with the ampersand character and followed by thesemicolon. The semicolon may be omitted if the entity reference is followed by a space or recordend. When an SGML parser encounters such an entity reference, it immediately substitutes thevalue declared for the entity name. Thus, the passage ``The work of the &tei has only just begunwill be interpreted by an SGML processor exactly as if it read ``The work of the Text EncodingInitiative has only just begun. In the case of a system entity, it is, of course, the contents of theoperating system file which are substituted, so that the passage ``The following text has beensuppressed: will be expanded to include the whole of whatever the system finds in the filesgmlmkup.txt. This obviously saves typing, and simplifies the task of maintaining consistency in a set ofdocuments. If the printing of a complex document is to be done at many sites, the document bodyVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 56
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHitself might use an entity reference, such as &site;, wherever the name of the site is required.Different entity declarations could then be added at different sites to supply the appropriate stringto be substituted for this name, with no need to change the text of the document itself. This string substitution mechanism has many other applications. It can be used tocircumvent the notorious inadequacies of many computer systems for representing the full rangeof graphic characters needed for the display of modern English (let alone the requirements ofother modern scripts or of ancient languages). So-called`special characters not directly accessiblefrom the keyboard (or if accessible not correctly translated when transmitted) may be representedby an entity reference. Suppose, for example, that we wish to encode the use of ligatures in early printed texts. Theligatured form of `ct might be distinguished from the non-ligatured form by encoding it as&ctlig; rather than ct. Other special typographic features such as leafstops or rules couldequally well be represented by mnemonic entity references in the text. When processing suchtexts, an entity declaration would be added giving the desired representation for such textualelements. If, for example, ligatured letters are of no interest, we would simply add a declarationsuch as<!ENTITY ctlig "ct" >and the distinction present in the source document would be removed. If, on the other hand, aformatting program capable of representing ligatured characters is to be used, we might replacethe entity declaration to give whatever sequence of characters such a program requires as theexpansion. A list of entity declarations is known as an entity set. Standard entity sets are provided foruse with most SGML processors, in which the names used will normally be taken from the lists ofsuch names published as an annex to the SGML standard and elsewhere, as mentioned above. The replacement values given in an entity declaration are, of course, highly systemdependent. If the characters to be used in them cannot be typed in directly, SGML provides aVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 57
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHmechanism to specify characters by their numeric values, known as character references. A characterreference is distinguished from other characters in the replacement string by the fact that it beginswith a special symbol, conventionally the sequence `&#, and ends with the normal semicolon. Forexample, if the formatter to be used represents the ligatured form of ct by the characters c and tprefixed by the character with decimal value 102, the entity declaration would read:<!ENTITY ctlig "&#102;ct" > Note that character references will generally not make sense if transferred to anotherhardware or software environment: for this reason, their use is only recommended in situationslike this. Useful though the entity reference mechanism is for dealing with occasional departuresfrom the expected character set, no one would consider using it to encode extended passages, suchas quotations in Greek or Russian in an English text. In such situations, different mechanisms areappropriate. These are discussed elsewhere in these Guidelines A special form of entities, parameter entities, may be used within SGML markup declarations;these differ from the entities discussed above (which technically are known as general entities) intwo ways: • Parameter entities are used only within SGML markup declarations; with some special exceptions which will not be discussed here, they will normally not be found within the document itself. • Parameter entities are delimited by percent sign and semicolon, rather than by ampersand and semicolon. Declarations for parameter entities take the same form as those for general entities, but insert apercent sign between the keyword ENTITY and the name of the entity itself. White space (blanks,tabs, or line breaks) must occur on both sides of the percent sign. An internal parameter entityVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 58
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHnamed TEI.prose, with an expansion of INCLUDE, and an external parameter entity namedTEI.extensions.dtd, which refers to the system file mystuff.dtd, could be declared thus:<!ENTITY % TEI.prose INCLUDE><!ENTITY % TEI.extensions.dtd SYSTEM mystuff.dtd>The TEI document type definition makes extensive use of parameter entities to control theselection of different tag sets and to make it easier to modify the TEI DTD.4. Write the SGML Structure? The simple and consistent mechanism for the markup or identification of structural textual unitswhich is provided by SGML. It also describes the methods SGML provides for the expression of rulesdefining how combinations of such units can meaningfully occur in any text.4.1 Elements The technical term used in the SGML standard for a textual unit, viewed as a structuralcomponent, is element. Different types of elements are given different names, but SGML providesno way of expressing the meaning of a particular type of element, other than its relationship toother element types. That is, all one can say about an element called (for instance) <blort> is thatinstances of it may (or may not) occur within elements of type <farble>, and that it may (or maynot) be decomposed into elements of type <blortette>. It should be stressed that the SGMLstandard is entirely unconcerned with the semantics of textual elements: these are applicationdependent. It is up to the creators of SGML conformant tag sets (such as these Guidelines) tochoose intelligible names for the elements they identify and to document their proper use in textmarkup. That is one purpose of this document. From the need to choose element names indicativeof function comes the technical term for the name of an element type, which is generic identifier, orGI.VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 59
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH Within a marked up text (a document instance), each element must be explicitly marked ortagged in some way. The standard provides for a variety of different ways of doing this, the mostcommonly used being to insert a tag at the beginning of the element (a start-tag) and another at itsend (an end-tag). The start- and end- tag pair are used to bracket off the element occurrenceswithin the running text, in rather the same way as different types of parentheses or quotationmarks are used in conventional punctuation. For example, a quotation element in a text might betagged as follows: ... Rosalinds remarks <quote>This is the silliest stuff that ere I heard of!</quote> clearly indicate ... As this example shows, a start-tag takes the form <name>, where the opening angle bracketindicates the start of the start-tag, ``name is the generic identifier of the element which is beingdelimited, and the closing angle bracket indicates the end of a tag. An end-tag takes an identicalform, except that the opening angle bracket is followed by a solidus (slash) character, so that thecorresponding end-tag would be </name>.4.2 Content Models: An Example An element may be empty, that is, it may have no content at all, or it may contain simpletext. More usually, however, elements of one type will be embedded (contained entirely) withinelements of a different type. To illustrate this, we will consider a very simple structural model. Let us assume that wewish to identify within an anthology only poems, their titles, and the stanzas and lines of whichthey are composed. In SGML terms, our document type is the anthology, and it consists of a seriesof poems. Each poem has embedded within it one element, a title, and several occurrences ofanother, a stanza, each stanza having embedded within it a number of line elements. Fully markedup, a text conforming to this model might appear as follows:VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 60
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH <anthology> <poem><title>The SICK ROSE</title> <stanza> <line>O Rose thou art sick.</line> <line>The invisible worm,</line> <line>That flies in the night</line> <line>In the howling storm:</line> </stanza> <stanza> <line>Has found out thy bed</line> <line>Of crimson joy:</line> <line>And his dark secret love</line> <line>Does thy life destroy.</line> </stanza> </poem> <!-- more poems go here --> </anthology>It should be stressed that this example does not use the same names as are proposed forcorresponding elements elsewhere in these Guidelines: the above is not a valid TEIdocument. It will however serve as an introduction to the basic notions of SGML. Whitespace and line breaks have been added to the example for the sake of visual clarityonly; they have no particular significance in the SGML encoding itself. Also, the line <!-- more poems go here -->is an SGML comment and is not treated as part of the text. This example makes no assumptions about the rules governing, for example, whether or not aVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 61
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECHtitle can appear in places other than preceding the first stanza, or whether lines can appear whichare not included in a stanza: that is why its markup appears so verbose. In such cases, thebeginning and end of every element must be explicitly marked, because there are no identifiablerules about which elements can appear where. In practice, however, rules can usually beformulated to reduce the need for so much tagging. For example, considering our greatly over-simplified model of a poem, we could state the following rules: • An anthology contains a number of poems and nothing else. • A poem always has a single title element which precedes the first stanza and contains no other elements. • Apart from the title, a poem consists only of stanzas. • Stanzas consist only of lines and every line is contained by a stanza. • Nothing can follow a stanza except another stanza or the end of a poem. • Nothing can follow a line except another line or the start of a new stanza. From these rules, it may be inferred that we do not need to mark the ends of stanzas or linesexplicitly. From rule 2 it follows that we do not need to mark the end of the title---it is implied bythe start of the first stanza. Similarly, from rules 3 and 1 it follows that we need not mark the endof the poem: since poems cannot occur within poems but must occur within anthologies, the endof a poem is implied by the start of the next poem, or by the end of the anthology. Applying thesesimplifications, we could mark up the same poem as follows: <anthology> <poem><title>The SICK ROSE <stanza> <line>O Rose thou art sick. <line>The invisible worm, <line>That flies in the nightVEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 62
    • VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH <line>In the howling storm: <stanza> <line>Has found out thy bed <line>Of crimson joy: <line>And his dark secret love <line>Does thy life destroy. <poem> <!-- more poems go here --> </anthology> The ability to use rules stating which elements can be nested within others to simplify markupis a very important characteristic of SGML. ****************VEL TECH VEL TECH MULTI TECH VEL TECH HIGH TECH 63