ms-54

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MS-54 REFERENCE MATERIAL Q1. Discuss the rational individual models of decision making. What are the implications of these models to information system analysts?

Rational decision making models involve a cognitive process where each step follows in a logical order from the one before. By cognitive, I mean it is based on thinking through and weighing up the alternatives to come up with the best potential result. There are different types of rational models and the number of steps involved, and even the steps themselves, will differ in different models. Some people assume that decision making is equivalent to problem solving. Some decisions however are not problem oriented and I've taken this into consideration when describing the general outline of a rational model below Steps in a rational decision making model • Define the situation/decision to be made Identify the important criteria for the process and the result • Consider all possible solutions • • •

Calculate the consequences of these solutions versus the likelihood of satisfying the criteria Choose the best option

Phases of decision-making process are: • •

• • •

Intelligence- searching for conditions in the environment that call for decisions Design- inventing, developing, and analyzing possible courses of action Choice- selecting a course of action from those available Implementation- implementing the selected course of action Monitoring- checking the consequences of the decision made after implementation

The comparison is often performed by filling out forms or charts that have many names. Decision matrix, Pugh matrix, decision grid, selection matrix, criteria rating form, amongst others. A relative importance is given to each criterion and the options are scored against each of the criteria and the highest 'wins'. Pros and cons A rational decision making model presupposes that there is one best outcome. Because of this it is sometimes called an optimizing decision making model. The search for perfection is frequently a factor in actually delaying making a decision.

Such Such a model model also also presup presuppos poses es that it is possible possible to consider know the future future consider every every option and also to know consequences of each. While many would like to think they know what will happen, the universe often has other plans! It is also limited by the cognitive abilities of the person making the decision; how good is their memory? How good is their imagination? The criteria themselves, of course, will be subjective and may be difficult to compare. These models require a great deal of time and a great deal of information. And, of course, a rational decision making model attempts to negate the role of emotions in decision making. Specific types of rational decision making models Bounded rational decision making models A decisi decision on maker maker is said said to exhibit exhibit bounded bounded ration rationali ality ty when when they they consid consider er fewer fewer option optionss than than are actua actually lly available, or when they choose an option that is not ?the best overall? but is best within the current circumstances. Eg, someone spills coffee on a shirt in a restaurant, and goes next door and buys a poorly fitting shirt to change into immediately.

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Obviously it would be optimal to buy a proper fitting shirt. But if the person is in a hurry and cannot wear a wet, coffee stained shirt, then buying the poorly fitting one is appropriate. This is an example of bounded rationality. Vroom-Jago decision model This model originally was created by Vroom and Yetton in 1973 and later modified by Vroom and Jago. Basically there are five situations for making decisions, from a single individual making the decision, to an individual making the decision with varying amounts of input from the rest of the group, to the whole group making the decision.

The Vroom-Jago decision model has a series of seven yes/no questions that elicit the important criteria and indicate which of the five decision-making processes is the most appropriate Intuitive decision making models Some people consider these decisions to be unlikely coincidences, lucky guesses, or some kind of new-age hocus pocus. Many universities are still only teaching rational decision making models and suggest that if these are not used, failure results. Some researchers are even studying the logic behind the intuitive decision making models! The groups who study intuitive intuitive decision making models are realising realising that it's not simply the opposite opposite of rational rational decision making. Carl Jung pointed out that it is outside the realm of reason. In military schools the rational, analytical models have historically been utilised. It is also long been recognised, however, that once the enemy is engaged the analytical model may do more harm than good. History is full of examples where battles have more often been lost by a leader? Failure to make a decision than by his making a poor one. A good plan, executed now, is better than a perfect plan next week." - General George S. Patton, Jr. The military are educating the soldiers of every rank in how to make intuitive decisions. Information overload, lack of time and chaotic conditions are poor conditions for rational models. Instead of improving their rational decision making, the army has turned to intuitive decision models. Why? Because they work! The ultimate decision making model The ultimate model will allow you to rapidly assimilate the available information in a situation, bring all the relevant learning and past experiences to bear and allow you to quickly and easily decide what to do, while knowing for certain that you're making the right decision. Recognition primed decision making model Psychologist Dr Gary Klein has been studying decision making for many years and he suggests that people actually use an intuitive approach 90% of the time. His recognition primed decision making model describes that in any situation there are cues or hints that allow people to recognise patterns. Obviously the more experience somebody has, the more patterns they will be able to recognise. Based on the pattern, the person chooses a particular course of action. They mentally rehearse it and if they think it will work, they do it.

If they don't think it will work, they choose another, and mentally rehearse that. As soon as they find one that they think think will will work, work, they they do it. Again past experie experience nce and learni learning ng plays plays a big part here. here. There is no actual actual comparison of choices, but rather a cycling through choices until an appropriate one is found. Today’s managers depend on information systems for decision making. The managers have handful of data around them but manually they cannot process the data accurately and with in the short period of time available to them due to heavy competition in modern world. Therefore mangers depend on information systems. The concept of MIS: Management: Management has been defined in a variety of ways, but for our purposes it comprises the process or activities what managers do in the operation of their organization: Plan, Organize, Initiate and Control operations. Information: 2


Data are facts and figures that are not currently being used in a decision processes and usually take the form of historical records that are recorded and filed without immediate intent to retrieve for decision making. Information consists of data that have been retrieved, processed or otherwise used for information or inference purposes, argument, or as a basis for forecasting or decision making. System can be described simply as a set of elements joined together for a common objective. A subsystem is part of a larger system with which we are concerned. All systems are part of larger systems. The objective of an MIS (Manag (Manageme ement nt Inform Informati ation on System System)) is to provid providee inform informati ation on for decisi decision on making making on planni planning, ng, initia initiating ting,, organizing, and controlling the operations of the subsystems of the form and to provide a synergetic organization in the process. Decision Support System: It is sometimes described as the next evolutionary step after Management Information Systems Systems (MIS). MIS support support decision decision making in both structured structured and unstructured unstructured problem environments.. environments.. It supports decision making at all levels of the organization .IS (Information Systems) are intended to be woven into the fabric of the organizations, not standing alone. IS support all aspects of the decision making process.MIS are made of people, computers, procedures, databases, interactive query facilities and so on. They are intended to be evolutionary/adaptive and easy for people to use Methods of Decision Making

Type Of Decision Prog Progra ramm mmed ed Repe Repetit titiv ivee and and rout routin inee

Non - Programmed

Methods of decision making Old Habi Habitt standard operating Procedure Organization structure , policy etc Judgement Intuition, Insight experience, Training and Learning

New Management information system

Systematic Approach to problem solving & Decision Making

MIS is a technique for making programmed decisions. If we include the computer and management science as integral parts or tools of computer-based information systems, the prospects for a revolution in programmed decision making are very real. Just as a manufacturing process is becoming more and more automated so is the automation of programmed decisions increasing to support this production and other information needs through out the organization. System Design & Decision Making The purpose of elaborating the concept of decision making in the context of IS was to make you realize the importance importance of the fact that, Information Information system must support support the managers for timely and effective decision decision making. While designing the information system, output, in terms of suitable reports is essential to analyze, highlight and bring to attention situations that may require decision making. The top manager looks for value addition to his/her knowledge of business operation.

Q2. Discuss the critical success factor method for the purpose of information requirement analysis

Requirements analysis in systems engineering and software engineering, encompasses those tasks that go into determining determining the needs or conditions conditions to meet for a new new or altered altered produc product, t, taking taking account account of the possibly possibly conflicting requirements of the various stakeholders, such as beneficiaries or users. Requirements analysis is critical to the success of a development project. Requirements must be documented, actionable, measurable, testable, related to identified business needs or opportunities, and defined to a level of detail sufficient sufficient for system system design. design. Requiremen Requirements ts can be architectu architectural, ral, structural, structural, behavioral, behavioral, functional, functional, and nonfunctional.

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The IS requirements-gathering process is a critical first step in the IS development or adoption process. However, IS requirements are too frequently incomplete, inconsistent, or incorrect. Often, the reasons for this failure have less to do with technologies than with people and management. Five CSFs for IS requirements gathering 1. Management commitment to the project Management commitment to the project was described as the level of importance that upper-level management placed on the successful completion of the project. In general, management commitment refers to the emotional or psych psycholo ologic gical al obliga obligation tion that that upper upper manage managemen mentt demons demonstra trates tes toward toward the projec project. t. It is not surpris surprising ing that that management commitment was selected as the most important factor when all the factors were considered. Not only does management commitment drive individuals to perform because they wish to achieve recognition from their superiors, but management commitment is directly linked to whether adequate financial, human, and technology resources would be available. Several things can be done to ensure that a project has adequate management commitment prior to the project’s launch. One is to require the presence of a champion for the project. A champion is a high-level manager within the organization who acts as sponsor and leader for the project. The champion should possess enough clout within the organization to gain necessary resources and exposure for the project to succeed. Another way to ensure management commitment to a project prior to IS requirements gathering is to have a formal project project proposal proposal process process in place. place. This process should include the feasibility feasibility analysis analysis (including (including economic, technical, and human resources aspects) and some type of capital budgeting or investment comparison that will clearly show the financial returns for the project. For smaller firms, at least a cost/benefit analysis should be performed and the payback period and break-even point for the IT investment should be estimated and compared to other investment opportunities. The final step of this process is approval of the proposal by management that will be held accountable for the project’s success or failure. One last approach to improve management commitment to a project is to clearly communicate the importance of the project to all the departments, divisions, work groups, etc., by having a kick-off event or information session sponsored by the manager whose span of control covers all of these areas. This will send the clear message to the managers, users, and IT personnel involved that the project has the backing of high-level management. Alternatively, a letter or e-mail communication from the CEO or CIO may achieve the same result if it is specific in explaining the outcomes to be achieved and the importance of the project 2. Interaction between users and IS personnel Inte Intera ract ctio ion n betw betweeen use users and and IS pers person onne nell was des describe ribed d as the qua quantit ntity y and qua quality lity of comm commun unic icat atio ion n and the amoun mountt of grou group p activi tiviti ties es perf perfor orme med, d, incl includ udin ing g fee feedbac dback k from from and to one another during the process. Interaction is distinguished from communication by the inclusion of other behaviors being performed jointly by the users and IS personnel. Perhaps the most interesting aspect of this factor is that there is an inverse relationship between the quantity of interaction between users and IS personnel and the quality of this interaction. Apparently, when more time is needed for users and IS personnel to interact during a project, it is a symptom of other problems. That is, unusually greater amounts of inte intera ract ctio ion n betw betwee een n use users and IS pers person onne nell have have a nega negati tive ve impa impact ct on the the quali uality ty of the the information obtained. The rationale for this phenomenon is that when there are other “issues” not directly relevant to the IS requirements being addressed, a greater amount of time is spent communicating or interacting during the requirements-gathering process. Therefore, increased levels of communication (i.e., more meetings than is normally expected or a higher number of conference calls or personal visits among team members) may indicate other problems with the project (a lack of understanding of requirements, politics, etc.)that may impact the success of the project. To improve improve the quality quality of interaction interaction among users and IS personnel personnel during IS requiremen requirements ts gathering, gathering, managers have several alternatives. One is to take advantage of joint application development (JAD) or other group meeting techniques that use a neutral facilitator to run structured meetings to gather requirements. A good facilitator should be able to keep the user and IS participants focused on the goal of specifying the IS requirements. In addition, it has been suggested that assigning IS developers to the functional areas to perform the tasks to be suppor supported ted by the new system system also also improv improves es the quality quality of intera interacti ction on betwe between en users users and IS person personnel nel.. By performing performing the tasks in a functional functional area, IS personnel personnel develop a deeper deeper understand understanding ing of the business processes processes 4


and gain an appreciation for the functions and features needed in the new system as well as the constraints that may impact a computer-based system. 3. Goal congruence among IS, users, and management Defined as the agreement among management, user groups, and the IS department on the purpose of the project and the delive deliverab rables les to be produc produced, ed, goal goal congru congruenc encee was rated the third third most most importa important nt factor factor to succes successfu sfull IS requirements gathering. This factor is directly affected by the existence and quality of a feasibility study and plan. The The feas feasib ibil ilit ity y study tudy shou should ld incl includ udee info inform rmat atio ion n rega regard rdin ing g the the scop scopee of the the syste ystem m and the the goal goalss to be achie hieved. ved. In gene genera ral, l, both both expl xplicit icit and impli mpliccit goa goals are assoc ssocia iate ted d with with every project, and to be successful, substantive agreement is needed on these goals. This factor may also be affected by the interaction among users and IS personnel discussed above. It is expected that high-quality interaction would lead to a high level of goal congruence. However, goal congruence is clearly a distinct factor as the interaction may be high quality, but there still may be misunderstanding or conflict among the stakeholders with regard to the goals of the project. Anot Anothe herr aspec spectt of goal goal congr ongrue uenc ncee is the the diff diffic icul ulty ty enco ncounte untere red d whe when more more than than one use user area is involved with the project. Today, almost every information system in an organization impacts more than one functional area (some touch on every area, e.g., ERP systems). Usually, these different functional groups can have different, if not competing, requirements for the system. This makes the achievement of goal congruence more difficult. This is not intended to mean that a system cannot meet multiple goals. However, all of the goals of the project should be made explicit, public, and as concrete as possible. Finally, Finally, there may exist exist unsee unseen n or hidden hidden goals. goals. These These hidden hidden agendas agendas could could come come from from any area, such such as management, IS, or user groups, and could be benign and legitimate or could be intended to sabotage or damage the project. In general, the best approach to achieve goal congruence is to explicitly recognize and describe the goals and to restrict the scope of the project to the fewest number of functional areas possible. 4. IS personnel’s understanding of the application IS person personnel nel’s ’s unders understan tandin ding g of the applic applicati ation on is define defined d as how well well the inform informati ation on system systemss person personnel nel understand the purpose, the tasks, and the outputs of the work processes that the application is to support. This is typically referred to as domain knowledge. The involvement of IS personnel— who have knowledge regarding the application domain for which requirements are being defined—greatly increases the ability of the team to correctly and quickly specify the requirements. Specifically, having IS personnel on the team who have had prior experience in the domain area (e.g., by developing similar applications or doing support work, or best of all, performing some of the users’ job functions) allows IS personnel to understand terminology and have a deeper understanding of the users’ needs. The IS personnel’s level of domain knowledge would also be expected to positively impact the quality of the requirements-gathering process. By being familiar with the terms and business processes under study, semantic confusion should be avoided and communication improved. However, there also may be negative effects of IS personnel experience and domain knowledge within a specific area. This may manifest in a form of bias. Bias has been defined as a willingness to change or to try new approaches or as the resistance to new ideas and change. This second type of bias may be relevant because an IS developer may have been involved in earlier projects for the same system and be resistant to new ideas or technology or to doing things in ways different from before. 5. Planning The The planning factor was described as the amou mount of preparatio tion performed for the IS requirements-gathering process and included the identification of specific tasks and the person responsible for performing them. Studies have shown that a work plan and schedule for completion are necessary for project success. Reports of projects where an effort was nominally started without a specific plan or schedule, only to be forgotten in short order, are not unusual in most organizations. Also, stories abound where a project was begun with planned work activities and a schedule was laid out but no tasks were assigned to specific individuals, and everyone was surprised when the first set of milestones occurred and no work had been done.

Q3. Explain the concept of System and its usefulness in MIS. 5


Fundamental Information System Concepts • That Computer networks are systems of information processing components. • That Business uses of Computer networks are really Inter connected business information systems. That developing ways to use computer networks in business includes designing the basic components of • information systems.

That That mana managin ging g info inform rmat ation ion tech techno nolo logy gy emph emphas asiz izes es the qual qualit ity, y, busi busine ness ss valu value, e, and and secu securi rity ty of an organization’s information systems. System is a group of interrelate components working together toward a common common goal by accepting accepting input and producing outputs in an organized transformatio transformation n process. process. System has three basic interacting components or Functions: 1. Input 2. Processing 3. Output •

Involves capturing capturing and assembling assembling elements that enter the system system to be processed. processed. For ex. Raw 1. Input: Involves materials, energy, data, and human effort must be secured and organized for processing. that convert into output. Ex: manufacturing process, the human 2. Processing involves transformation processes that breathing process or mathematical calculations. 3. Output involves transferring elements that have been produced by a transformation process to their ultimate

destination. E.g.finished products, human services, and management information must be transmitted to their human users. The system concept becomes even more useful by including two addition components: feedback and control. A system with feedback and control components is sometimes called a Cyber ne tic system that is self monitoring and self regulating system. Feedback: is data about the performance of a system. Ex. Data about sales performance is feedback to a sales manager. Control: invo involv lvees moni monito tori ring ng and evalu valuaating ting feed feedb back ack to dete etermin rminee whet whethe herr a syst system em is moving toward the achievement of its goal. The control function then makes necessary adjustments to a system’s input and processing components to ensure that it produces proper output. A business is an organizational system where economic resources of (input) are transformed by various organization processes (processing) into goods and servic services es (outpu (output). t). Inform Informati ation on System Systemss provid providee inform informati ation on (feedb (feedbac ack) k) on the operat operation ionss of the system system to management for the direction and maintenance of the system (control), as it exchanges inputs and outputs with its environment. Components of Information System Information system Model that expresses a fundamental conceptual framework for major components and activities of information systems. Information System depends on the resources of 1. People People (End (End user user and IS spec special ialist ists) s) 2. Hard Hardwa ware re (Ma (Mach chin inee and and Media Media)) 3. Soft Softwa ware re (Prog (Progra ram m and proce procedu dure res) s) 4. Data Data (Da (Data ta and and kno knowl wled edge ge bas base) e) 5. Networ Network k (commu (communic nicati ation on media and Network Network support) support) to perfor perform m input, input, process processing ing,, output output,, storag storagee and control activities that convert data resources into information products

Information system model highlights the relationships among the components and activities of information systems. It provides a framework that emphasizes four major concepts that can applied to all types of information systems. There are the five basic resources of information system. • People resources include end users and are specialists Specialist: - System analysis, programmer, computer operators. End user: - any one else who uses information • system. 6


• • • •

•

hardware resources consist of machine and media, Machines: Computers, Video monitors, magnetic disk drive, printers, output scanners. Media: Floppy disk, magnetic tape, optical disks, paper forms, plastic card. Software resources include both programs and procedures, Programs: operating system, spreadsheet programs, word processing programs, payroll program

Information System Activities Input: - Optical scanning of bar-code tags on merchandise. • • Processing: - Calculating employee pay, taxes and other payroll deductions. • Output: - Producing reports and display about sales performance. Storage: -Maintaining records on customers, employees, and products. • Control: -Generating audible single to indicate proper entry of sales data. • Overview of Information System s Information system plays three information roles in the business success of an enterprise. Support of its business processes and operations. • • Support of decision making by its managers. • Support of its strategies for competitive advantage

Q4. Discuss the various Kinds of network topologies Network Topologies In computer networking, topology refers to the layout of connected devices. Network topologies are categorized into the following basic types:

bus • ring star • • tree • mesh More complex networks can be built as hybrids of two or more of the above basic topologies. Bus Topology Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with with an interf interface ace connecto connector. r. A device device wantin wanting g to commun communica icate te with with anothe anotherr device device on the networ network k sends sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message. Ethernet bus topologies are relatively easy to install and don't require much cabling compared to the alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet cabling options many years ago for bus topologies. However, bus networks work best with a limited number of devices. If more than a few dozen computers are added to a network bus, performance problems will likely result. In addition, if the backbone cable fails, the entire network effectively becomes unusable. This diagram illustrates the bus network topology. A bus topology such as 10Base-2 or 10Base-5 Ethernet uses a single communication backbone for all devices. •

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Bus Network Topology Ring Topology In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" "clockwise" or "counterclockwise"). "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network. To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring topologies are found in some office buildings or school campuses. This diagram illustrates the ring network topology. A ring topology such as FDDI or SONET sends messages clockwise or counterclockwise through the shared link

Ring Network Topology Star Topology Many home networks use the star topology. A star network features a central connection point called a "hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet. Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer's computer's network access access and not the entire LAN. (If the hub fails, however, the entire network also fails.) This diagram illustrates the star network topology. A star topology typically uses a network hub or switch and is common in home networks.

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Star Network Topology Tree Topology

Tree Tree topo topolo logi gies es inte integr grat atee mult multip iple le star star topo topolo logi gies es toge togeth ther er onto onto a bus. bus. In its its simp simple lest st form form,, only only hub hub devi device cess conne onnect ct dire direcctly tly to the the tree tree bus, bus, and each each hub hub func functi tion onss as the the "roo "root" t" of a tree of devices. This bus/star hybrid approach supports future expandability of the network much better than a bus (limited in the number of devices due to the broadcast traffic it generates) or a star (limited by the number of hub connection points) alone. This diagram illustrates the tree network topology. A tree topology integrates the star and bus topologies in a hybrid approach to improve network scalability.

Tree Network Topology Mesh Topology Mesh topologies topologies involve involve the concept of routes. routes. Unlike each of the previous previous topologies, topologies, messages sent on a mesh network can take any of several possible paths from source to destination. (Recall that even in a ring, although two cable paths exist, messages can only travel in one direction.) Some WANs, most notably the Internet, employ mesh routing. A mesh network in which every device connects to every other is called a full mesh. As shown in the illustration below, partial mesh networks also exist in which some devices connect only indirectly to others.

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This diagram illustrates the mesh network topology. A mesh topology provides redundant communication paths between some or all devices (partial or full mesh).

Mesh Network Topology Summary Topologies remain an important part of network design theory. You can probably build a home or small business computer network without understanding the difference between a bus design and a star design, but becoming familiar with the standard topologies gives you a better understanding of important networking concepts like hubs, broadcasts, and routes.

Q5. Outline the basic sequences of steps to acquiring a DBMS.

The database management system, or DBMS, is a computer software program that is designed as the means of managing all databases that are currently installed on a system hard drive or network. Different types of database management systems exist, with some of them designed for the oversight and proper control of databases that are configured for specific purposes. Here are some examples of the various incarnations of DBMS technology that are currently in use, and some of the basic elements that are part of DBMS software applications. As the tool that is employed in the broad practice of managing databases, the DBMS is marketed in many forms. Some of the more popular examples of DBMS solutions include Microsoft Access, FileMaker, DB2, and Oracle. All these products provide for the creation of a series of rights or privileges that can be associated with a specific user. This means that it is possible to designate one or more database administrators who may control each function, as well as provide other users with various levels of administration rights. This flexibility makes the task of using DBMS methods to oversee a system something that can be centrally controlled, or allocated to several different people. A DBMS is a software package that carries out many different tasks including the provision of facilities to enable the user to access and modify information in the database. The database is an intermediate link between the physical database, computer and the operating system and the users. To provide the various facilities to different types of users, a DBMS normally provides one or more specialized programming languages called database languages. 10


Functions of DBMS DBMS free the programmers from the need to worry about the organization and • location of the data i.e. it shields the users from complex hardware level details. • DBMS can organize process and present data elements from the database. This capability enables decision makers to search and query database contents in order to extract answers that are not available in regular Reports. • Programming is speeded up because programmer can concentrate on logic of the application. It includes special user friendly query languages which are easy to understand by non programming users of the • system. The various common examples of DBMS are Oracle, Access, SQL Server, Sybase, FoxPro, Dbase etc.

The service provided by the DBMS includes: Authorization services like log on to the DBMS, start the database, stop the Database etc. • • Transaction supports like Recovery, Rollback etc, • Import and Export of Data. • Maintaining data dictionary User's Monitoring • ADVANTAGES OF DBMS

The DBMS (Database Management System) is preferred ever the conventional file Processing system due to the following advantages: 1. Controlling Data Redundancy - In the conventional file processing system, every user group maintains its own files for handling its data files. This may lead to • • • • • •

Duplication of same data in different files. Wastage of storage space, since duplicated data is stored. Errors may be generated due to updating of the same data in different files. Time in entering data again and again is wasted. Computer Resources are needlessly used. It is very difficult to combine information.

the file file proc proces essi sing ng sys system tem info inform rmat atio ion n is dupl duplic icat ated ed 2. Elim Elimin inat atio ion n of Inco Incons nsis iste tenc ncy y - In the thr throughout the the system. So changes made in one file may be necessary be carried over to another file. This may lead to inconsistent data. So we need to remove this duplication of data in multiple file to eliminate inconsistency. For example: - Let us consider an example of student's result system. Suppose that in STU¬DENT file it is indicated that Roll no= 10 has opted for 'Computer' course but in RESU RESULT LT file file it is indi indiccate ated tha that 'Roll Roll No. =l 0' has has opte pted for for 'Acco Accou unts nts' cours ourse. e. Thu Thus, in this case the two entries for z particular student don't agree with each other. Thus, data databa basse is said said to be in an inc incons onsiste istent nt sta state. te. Sc to elim elimin inat atee this this con conflic flicti ting ng info inform rmat atio ion n we need need to cent central ralize ize the the datab databas ase. e. On cent central ralizi izing ng the the data data base base the dupl duplica icatio tion n will will be contr controll olled ed and and hence hence inconsistency will be removed. Data Data inc incons onsiste istenc ncy y are ofte often n encou ncount nteered red in every very day day life life Cons Consid ideer an anoth notheer examp xample le,, we have all come across situations situations when a new address is communicated to an organization organization that we deal deal it (EgTelecom, Gas Company, Bank). We find that some of the communications from that organization are received at a new address while other continued to be mailed to the old address. So combining all the data in database would involve reduction in redundancy as well as inconsistency so it is likely to reduce the costs for collection storage and updating of Data. Let Let us again gain consi onside derr the the examp xample le of Resu Result lt sys system. tem. Supp Suppos osee that that a stude tuden nt havi havin ng Roll oll no -201 changes his course from 'Computer' to 'Arts'. The change is made in the SUBJECT file but not in RESULT'S file. This may lead to inconsistency of the data. So we need to centralize the database so that changes

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once made are reflected to all the tables where a particulars field is stored. Thus the update is brought automatically and is known as propagating updates. 3. Better service to the users - A DBMS is often ten used to provide better services to the users. users. In conventiona conventionall system, system, availabilit availability y of information information is often poor, since it normally difficult to obtain information that the existing systems were not designed for. Once several conventional systems are combined to form one centralized database, the availability of information and its updateness is likely to improve since the data can now be shared and DBMS makes it easy to respond to anticipated information requests. Centralizing the data in the database also means that user can obtain new and combined information easily that would would have have been been imposs impossible ible to obtain obtain otherwis otherwise. e. Also Also use of DBMS DBMS should should allow users users that that don't don't know know programming to interact with the data more easily, unlike file processing system where the programmer may need to write new programs to meet every new demand. 4. Flexibility of the System is improved - Since changes are often necessary to the contents of the data stored in any system system,, these these change changess are made more more easil easily y in a centr centrali alized zed database database than in a conven conventio tional nal system system.. Applications programs need not to be changed on changing the data in the database. 5. Integrity can be improved - Since data of the organization using database approach is centralized and would be used by a number of users at a time. It is essential to enforce integrity-constraints. In the conventional systems because the data is duplicated in multiple files so updating or changes may sometimes lead to entry of incorrect data in some files where it exists.

For example: - The example of result system that we have already discussed. Since multiple files are to maintained, as sometimes you may enter a value for course which may not exist. Suppose course can have values (Computer, Accounts, Economics, and Arts) but we enter a value 'Hindi' for it, so this may lead to an inconsistent data, so lack of Integrity. Even if we centralized the database it may still contain incorrect data. For example: • • •

Salary of full time employ may be entered as Rs. 500 rather than Rs. 5000. A student may be shown to have borrowed books but has no enrollment. A list of employee numbers for a given department may include a number of non existent employees.

These problems can be avoided by defining the validation procedures whenever any update operation is attempted. 6. Stan Standa darrds can be enfo enforrced ced - Sinc Sincee all all acc access ess to the the data databa base se mus must be thro throug ugh h DBMS, BMS, so stand tandaards rds are eas easier ier to enfor nforce ce.. Stan Standa dard rdss may may rela relate te to the the nami naming ng of data data,, form formaat of data, structure of the data etc. Standardizing stored data formats is usually desirable for The purpose of data interchange or migration between systems.

conven enti tion onal al syst system ems, s, appl applic icat atio ions ns are are deve develo lope ped d in an 7. Sec Securi urity can be impro proved - In conv adhoc/temporary manner. Often different system of an organization would access different components of the operational data, in such an environment enforcing security can be quiet difficult. Setting up of a database makes it easier to enforce security restrictions since data is now centralized. It is easier to control who has access to what parts of the database. database. Different Different checks can be established for each type of access (retrieve, modify, delete etc.) to each piece of information in the database. Cons Consid ider er an Example of ban bankin king in whic which h the the emplo mploy yee at diff diffeerent rent leve levels ls may may be give given n access to differen rent types of data in the database. A clerk may be given the the authority to know only the names of all the customers who have a loa loan in bank but not the the details ils of eac each loan loan the the cust custom omer er may may have have.. It can be acc accompl omplis ishe hed d by givi giving ng the the priv priviilege legess to each ach employee. 8. Organization's requirement can be identified - All organizations have sections and departments and each of these units often consider the work of their unit as the most important and therefore consider their need as the most important. Once a database has been setup with centralized control, it will be necessary to identify organization's requirement and to balance the 12


needs of the competating units. So it may become necessary to ignore some requests for information if they conflict with higher priority need of the organization. It is the responsibili ility of the the DBA (Database Administrator) system to provide the overall service that is best for an organization.

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9. Overall cost of developing developing and maintaining maintaining systems is lower - It is much easier to respond to unanticipated requests when data is centralized in a database than when it is stored in a conventional file system. Although the initial cost of setting up of a database can be large, one normal expects the overall cost of setting up of a database, developing and maintaining application programs to be far lower than for similar service using conventional systems, systems, Since the productivity productivity of programmers programmers can be higher higher in using non-procedu non-procedural ral languages languages that have been developed with DBMS than using procedural languages. 10. Data Model must be developed - Perhaps the most important advantage of setting up of database system is the requirement that an overall data model for an organization be build. In conventional systems, it is more likely that files will be designed as per need of particular applications demand. The overall view is often not considered. Building an overall view of an organization's data is usual cost effective in the long terms.

11. Provides backup and Recovery - Centralizing a database provides the schemes such as recovery and backups from the failures including disk crash, power failures, software errors which may help the database to recover from the inconsistent state to the state that existed prior to the occurrence of the failure, though methods are very complex. Query, Data Manipulation, and Reporting Capabilities: The The DBM DBMS’s S’s abili bility ty to supp suppor ortt repo report rtin ing g requ requir ireement mentss, along long with ith use users’ rs’ que query and and data data mani manipu pula lati tion on need needs, s, is the the corn corner erst ston onee of toda today’ y’ss mana manage geme ment nt info inform rmat atio ion n syst system ems. s. A soun sound d DBMS is going to provide the capability to generate structured reports in a variety of formats. In addition, the DBMS will provide a query language that is powerful, yet easy to learn and use. The language should be able to support both planned and unplanned query requirements with short response times. Support of Specialized Programming Requirements: Develo Developin ping g specia specializ lized ed progra programs ms to interf interface ace with with the DBMS DBMS requir requires es facili facilitie tiess for suppor supportin ting g progra program m development and program testing. A worthy DBMS will provide a host language for expressing standard procedural program structures or will provide an interface capability for quick prototyping of applications. Physical Data Organization Options: The firm acquiring a DBMS may not wish to involve itself in the details of physical data organization. Instead, it may gauge the efficiency of a DBMS’s physical organization by running sample applications.

For those who are interested, however, exploring the physical organization features may be of value. For example, it is known that the inverted list is most efficient in supporting multikey retrieval, whereas the chain list is superior for file updating since there is no need for updating a separate file. Information on other architectural features may be elicited in the process of considering the DBMS’s capability to support the types of applications common to the firm Steps to acquiring a DBMS The steps in developing any application can be represented as a linear sequence (Pressman, 2000) where each step in the sequen sequence ce is a functi function, on, which passes passes its output output to its succes successor sor functi function. on. Adhere Adherence nce of a 'water 'waterfal falll development model' ensures quality software, which is 'complete', 'efficient', 'usable', 'consistent', 'correct' and 'flexible'. These traits are also some of the core underpinnings of a well-built database (Moody & Shanks, 2002). The waterfall model can be applied to database design theory as effectively as it is applied to other software engineering theory. The steps can be summarized as follows (Batini et al.,1986):

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Requirements specification -> Analysis -> Conceptual design -> Implementation Design-> Physical Schema Design and Optimisation Data Models & Schemas as a Means of Capturing Data The database development design phase brings up the concept of 'data models'. Data models are diagrams or schemas, which are used to present the data requirements at different levels of abstraction. The first step in the Database Development Life Cycle is to draw up a requirements document. The requirements document can then be analysed and turned into a basic data set which can be converted into a conceptual model. The end result of the conceptual design phase is a conceptual data model which provides little information information of how the database database system will eventually eventually be implemente implemented. d. The conceptual conceptual data model is simply a high-level overview of the database system. In the implementation design phase, the conceptual data model is translated into a 'logical' representation of the database system. The logical data model conveys the "logical functioning and structure" of the database (Benyon, 1993) and describes 'how the data is stored' (Dan et al., 2007) (e.g. what tables are used, what constraints are applied) but is not specific to any DBMS. Logical database model is a lower-level conceptual model, which must be translated to a physical design Phys Physic ical al mode modell llin ing g deal dealss with with the the "rep "repre rese sent ntat atio iona nall aspe aspect cts" s" and and the the "ope "opera rati tion onal al aspe aspect cts" s" (Benyon & Murray, 1993) of the database, i.e. the internal DBMS specific operations and processes and how the DBMS interacts with the data, the database and the user. The translation from logical design to physical design assigns "functions" to both the machine (the DBMS) and to the user (Benyon & Murray, 1993), functions such as storage and security (Batini et al., 1986), and additional aspects such as consistency (of data) and learnability (Benyon & Murray, 1993) are dealt with in the physical model/schema. Practically speaking, a physical schema is the SQL code used to build the database. One benchmark benchmark of a good database database is one, which is complete, complete, integral, integral, simple, simple, understand understandable, able, flexible and implementable (Moody & Shanks, 2002). Batini et al says that database modelling strives for a "nonredundant, unifie unified d repres represent entati ation on of all data data manage managed d in an organi organizat zation ion"" (Batin (Batinii et al., al., 1986). 1986). By follow following ing the above above methodology, and and by usin using g the the data data mod models, els, the these data datab base ase desi design gn idea ideals ls are are fulf fulfil ille led d. In concl onclus usio ion, n, here are two examples of why using data models is paramount to capturing and Conveying data requirementsof the information system: (i) By drawing up a 'logical model', extra data items can be added more easily in that model then in the physical model. A database design that can change easily according to needs of the company is important; because it ensures the final database system is complete and up-to-date. (ii) Another consideration is understandability. By initially creating a 'conceptual model', both the designer and the organization are able to understand the database design and decide if it is complete or not. If there were no 'conceptual model', the organization would not be able to 'conceptualise' the database design and make sure that it actually represents represents all the data requirements of the organization.

(iii) By creating a physical model, the designers can have a low level overview of how the database system would operate before it is actually implemented. SQL Statements - Implementing the Database The final step is to physically implement the logical design which was illustrated in Figure 4. To physically implement the database, SQL can be used. These are the main steps in implementing the database: 1. Create the database tables. The tables come directly from the information contained in the Data Dictionary. The following blocks of code each represent a row in the data dictionary and are executed one after another. The blocks of "create table" code contain the details of all the data items (COMPANY, SUPPLIER, PURCHASES, EMPLOYEE etc), their attributes (names, ages, costs, numbers and other details), the Relationships between the data items, the Keys and Data Integrity Rules. All of this information is already detailed in the Data Dictionary, but now we are actually converting it and implementing it in a physical database system. 2. Populate the tables. Use SQL statements to populate each table with specific data (such as employee names, ages, wages etc). 14


3. Query the database. Write SQL statements to obtain information and knowledge about the company, e.g. how many employees are there, total profit etc. Keys & Data Integrity Rules Data integrity rules are a core component of a data model. Integrity rules "implicitly or explicitly define the set of consistent consistent database database state(s)". state(s)". So, integrity integrity rules "ensure "ensure that database database states and changes changes of state confirm to specified rules." Data integrity rules are of two types: Entity integrity rules and Referential integrity rules. (Codd, 1982).

How do keys relate to ensuring that changes in database states confirm to specified rules? Well, for example, you could ensure that the primary key of an entity cannot be null. This is one way of ensuring entity i ntegrity. If primary keys were allowed to be null, then there would be no way of ensuring that individual entities were uniquely identifiable. If you cannot ensure that individual entities are uniquely identifiable then you can't ensure that the database is 'integral', which is a core property of a properly designed data model (Moody & Shanks, 2002). So, by ensuring that keys follow certain rules, you can ensure integrity of data. Another way of enforcing int integrity of data via keys, is to ensure that, if two two tables are rela relate ted d to eac each othe other, r, an attr attrib ibut utee of one one rela relati tion on mus must be the the same same as the the prim primaary attr attrib ibut utee (primary key) of the other one. Enforcing this rule ensures referential integrity of data.

Q6. Differentiate among Trojans, Worms and Viruses. Give one example of each.

Viruses, worms and Trojan Horses are all malicious programs that can cause damage to your computer, but there are differences among the three. The most common blunder people make when the topic of a computer virus arises is to refer to a worm or Trojan horse as a virus. While the words Trojan, worm and virus are often used interchangeably, they are not exactly the same. Viruses, worms and Trojan Horses are all malicious programs that can cause damage to your computer, but there are differences among the three, and knowing those differences can help you to better protect your computer from their often damaging effects. Trojan Trojan, is softw oftwaare tha that appe ppears to perf perfor orm m a desir esiraable ble func functi tion on for for the use user prio priorr to run run or ins instal tall, but but (per (perha haps ps in add additio ition n to the the expec xpecte ted d func functi tion on)) ste steals als info inform rmaation tion or harm harmss the system

Purpose and uses Adware A destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to rid a computer of viruses but instead introduces viruses onto the computer. The term comes from the Greek story of the Trojan War, in which the Greeks give a giant wooden horse to their foes, the Trojans, ostensibly as a peace offering. But after the Trojans drag the horse inside their city walls, Greek soldiers sneak out of the horse's hollow belly and open the city gates, allowing their compatriots to pour in and capture Troy. Security Trojan horses may allow a hacker remote access to a target computer system. Once a Trojan horse has been installed on a target computer system, a hacker may have access to the computer remotely and perform various operations, limited by user privileges on the target computer system and the design of the Trojan horse. Operations that could be performed by a hacker on a target computer system include: • Use of the machine as part of a botnet (e.g. to perform automated spamming or to distribute Denial-ofservice attacks) Data theft (e.g. retrieving passwords or credit card information) • 15


Installation of software, including third-party malware • Downloading or uploading of files on the user's computer • Modification or deletion of files Keystroke logging • • Watching the user's screen • Crashing the computer Trojan horses in this way require interaction with a hacker to fulfill their purpose, though the hacker need not be the individual responsible for distributing the Trojan horse. It is possible for individual hackers to scan computers on a network using a port scanner in the hope of finding one with a malicious Trojan horse installed, which the hacker can then use to control the target computer. As mentioned earlier on, the term "Trojan horse" was taken from a clever Greek plan described by Homer in the Iliad. After seemingly abandoning the siege of Troy, the Greeks placed armed men inside a huge wooden horse. The horse was welcomed into the city by the Trojans, who believed it was a symbol of peace; they slept while the Greeks exited the horse and opened the gates allowing the Greek army into Troy, conquering the city. Current use Due to the popularity of botnets among hackers and the availability of advertising services that permit authors to violate their users' privacy, Trojan horses are becoming more common. According to a survey conducted by Bit Defender from January to June 2009, "Trojan-type malware is on the rise, accounting for 83-percent of the global malware detected in the world". This virus has a relationship with worms as it spreads with the help given by worms and travel across the internet with them •

Trojan are impostors—files that claim to be something desirable but, in fact, are malicious. A very important distinction between Trojan horse programs and true viruses is that they do not replicate themselves. Trojan horses contain malicious code that when triggered cause loss, or even theft, of data. For a Trojan horse to spread, you must invite these programs onto your computers; for example, by opening an email attachment or downloading and running a file from the Internet. Trojan. Vundo is a Trojan horse Worms Worms are programs that replicate themselves from system to system without the use of a host file. This is in contrast to viruses, which requires the spreading of an infected host file. Although worms generally exist inside of other files, often Word or Excel documents, there is a difference between how worms and viruses use the host file. Usually the worm will release a document that already has the "worm" macro inside the document. The entire docume document nt will will travel travel from from comput computer er to comput computer, er, so the entire docume document nt should should be consid considere ered d the worm worm W32.Mydoom.AX@mm is an example of a worm Virus A computer virus is a small program written to alter the way a computer operates, without the permission or knowledge of the user. A virus must meet two criteria: • •

It must execute itself. It often places its own code in the path of execution of another program. It must replicate itself. For example, it may replace other executable files with a copy of the virus infected file. Viruses can infect desktop computers and network servers alike.

Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply to replicate themselves and make their presence known by presenting text, video, and audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may l ead to system crashes and data loss. Five recognized types of viruses File File Insp Inspeector ctor Viru Viruse sess

File File infe infector tor viru virusses infe infecct prog progra ram m file files. s. These These viru viruse sess norm normaally lly infe infecct executable code, such as .com and .exe files. The can infect other files when an infected program is run from floppy, hard drive, or from the network. Many of 16


Boot oot Sec Sector tor virus irusees

Master Master Boot Boot reco record rd viru viruses ses

Mult Multip ipar arti tite te Virus irusees

Macro Viruses

these viruses are memory resident. After memory becomes infected, any no infected executable that runs becomes infected. Examples of known file infector viruses include Jerusalem and Cascade. Boot oot se sector ctor viru virusses infe infecct the the sys system tem are areaa of of a disk disk;; th that is, the the boo boott rec recor ord d on on floppy disks and hard disks. All floppy disks and hard disks (including disks containing only data) contain a small program in the boot record that is run when the computer starts up. Boot sector viruses attach themselves to this part of the disk and activate when the user attempts to start up from the infected disk. These viruses are always memory resident in nature. Most were written for DOS, but, all PCs, regardless of the operating system, are potential targets of this type of virus. All that is required to become infected is to attempt to start up your computer with an infected floppy disk Thereafter, while the virus remains in memory, all floppy disks that are not write protected will become infected when the floppy disk is accessed. Examples of boot sector viruses are Form, Disk Killer, Michelangelo, and Stoned. Master Master boot boot recor record d viruses viruses are are memory memory-re -resid sident ent virus viruses es that that infec infectt disks disks in the same manner as boot sector viruses. The difference between these two virus types is where the viral code is located. Master boot record infectors normally save save a legiti legitimat matee copy copy of the master master boot boot record record in a differ different ent location. location. Windows NT computers that become infected by either boot sector viruses or master boot sector viruses will not boot. This is due to the difference in how the operat operating ing system system access accesses es its boot boot inform informati ation, on, as compar compared ed to Window Windowss 98/Me. 98/Me. If your Windows Windows NT system system is formatted formatted with FAT partitions partitions you can usually remove the virus by booting to DOS and using antivirus software. If the boot partition is NTFS, the system must be recovered by using the three Windows NT Setup disks. Examples of master boot record infectors are NYB, AntiExe, and Unashamed. Mult Multip ipar arti tite te (a (also lso know known n as pol polyp ypar arti tite te)) viru viruse sess infe infect ct bo both boo boott rec records ords and and progr program am files. files. These These are particula particularly rly diffic difficult ult to repair repair.. If the boot boot area area is cleaned, cleaned, but the files are not, the boot area will be reinfected. reinfected. The same holds true for cleaning infected infected files. If the virus is not removed removed from the boot area, any files that you have cleaned will be reinfected. Examples of multipartite viruses include One-half, Emperor, Anthrax and Tequilla. These ty types of of vi viruses in infect da data fi files. Th They ar are th the mo most co common an and ha have cost corporations the most money and time trying to repair. With the advent of Visual Basic in Microsoft's Office 97, a macro virus can be written that not only infects infects data files, but also can infect infect other files as well. Macro viruses viruses infect infect Microsoft Office Word, Excel, PowerPoint and Access files. Newer strains are now turning up in other programs as well. All of these viruses use another program's internal programming language, which was created to allow users to automate certain tasks within that program. Because of the ease with which these viruses can be created, there are now thousands of them in circulation. Exampl Examples es of macro macro viruses viruses includ includee W97M.Me W97M.Melis lissa, sa, WM. Nice Nice Day and W97M.Groov.

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