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Introduction toSystem Analysis and

Design

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Defining A System

Organized set of related componentsestablished to accomplish certain task.

Basically there are three majorcomponents in every system, namely input,processing and output.

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Defining A System

In a SYSTEM the different components areconnected with each other and they are unableto exist or survive without each other.

For example:Human body represents a complete natural system.We are also bound by many national systems such aspolitical system, economic system, educationalsystem and so forth.

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SYSTEM LIFE CYCLE

System life cycle is an organizationalprocess of developing and maintainingsystems. It helps in establishing a system

project plan, because it gives overall list of processes and sub-processes requireddeveloping a system.

System development life cycle meanscombination of various activities. In otherwords we can say that various activities puttogether are referred as system development

life cycle.

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Phases Of Software Development Cycle

Following are the different phases of softwaredevelopment cycle:System studyFeasibility studySystem analysisSystem designCoding

TestingImplementationMaintenance

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(a) System StudyA detailed study to determine whether, to what extent, and how

automatic data-processing equipment should be used.

It usually includes an analysis of the existing system and the

design of the new system, including the development of systemspecifications which provide a basis for the selection of equipment.

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(b) Feasibility Studyaim to objectively and rationally uncover the strengths andweaknesses of the existing business or proposed venture,opportunities and threats as presented by the environment ,the resources required to carry through, and ultimately theprospects for success .

should provide a historical background of the business orproject, description of the product or service , accountingstatements, details of the operations andmanagement , marketing research and policies, financial data,legal requirements and tax obligations.

Generally, feasibility studies precede technical developmentand project implementation

http://en.wikipedia.org/wiki/Natural_environmenthttp://en.wikipedia.org/wiki/Resourceshttp://en.wikipedia.org/wiki/Successhttp://en.wikipedia.org/wiki/Product_(business)http://en.wikipedia.org/wiki/Service_(economics)http://en.wikipedia.org/wiki/Business_operationshttp://en.wikipedia.org/wiki/Managementhttp://en.wikipedia.org/wiki/Marketing_researchhttp://en.wikipedia.org/wiki/Projecthttp://en.wikipedia.org/wiki/Projecthttp://en.wikipedia.org/wiki/Marketing_researchhttp://en.wikipedia.org/wiki/Managementhttp://en.wikipedia.org/wiki/Business_operationshttp://en.wikipedia.org/wiki/Service_(economics)http://en.wikipedia.org/wiki/Product_(business)http://en.wikipedia.org/wiki/Successhttp://en.wikipedia.org/wiki/Resourceshttp://en.wikipedia.org/wiki/Natural_environment

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(c) System Analysis

is the study of sets of interacting entities , including computersystems analysis.

It is also "an explicit formal inquiry carried out to help someone

(referred to as the decision maker) identify a better course of action and make a better decision than he might otherwise havemade

http://en.wikipedia.org/wiki/Interactionhttp://en.wikipedia.org/wiki/Entityhttp://en.wikipedia.org/wiki/Entityhttp://en.wikipedia.org/wiki/Interaction

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(d) System Design

is the process of defining the architecture,components, modules, interfaces, and data fora system to satisfy specified requirements .

There are several tools and techniques used for

designing. These tools and techniques are:i. Flowchartii. Data flow diagram (DFDs)iii.Structured Englishiv. Decision tablev. Decision tree

http://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Systemhttp://en.wikipedia.org/wiki/Requirementhttp://en.wikipedia.org/wiki/Requirementhttp://en.wikipedia.org/wiki/Systemhttp://en.wikipedia.org/wiki/Data

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(e) Coding

* the process of designing, writing, testing, debugging / troubleshooting, and maintaining the source code of computerprograms. This source code is written in one or more programminglanguages . Means the transformation of data into a formunderstandable by computer software .

http://en.wikipedia.org/wiki/Programming_languagehttp://en.wikipedia.org/wiki/Programming_languagehttp://en.wikipedia.org/wiki/Data_transformationhttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Softwarehttp://en.wikipedia.org/wiki/Data_transformationhttp://en.wikipedia.org/wiki/Programming_languagehttp://en.wikipedia.org/wiki/Programming_language

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(f) Testing

a test run of the system is done removing all the bugs, if any. It is an important phase of a successful system. Aftercodifying the whole programs of the system, a test plan should

be developed and run on a given set of test data. The output of the test run should match the expected results.

When it is ensured that the system is running error-free,the users are called with their own actual data so that thesystem could be shown running as per their requirements.

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(g) Implementation

After having the user acceptance of the new system developed,the implementation phase begins. Implementation is the stageof a project during which theory is turned into practice. During

this phase, all the programs of the system are loaded onto theuser's computer. After loading the system, training of the usersstarts. Main topics of such type of training are:How to execute the packageHow to enter the dataHow to process the data (processing details)How to take out the reports

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(h) Maintenance

Maintenance is necessary to eliminate errors in the system duringits working life and to tune the system to any variations in its workingenvironment. It has been seen that there are always some errors found

in the system that must be noted and corrected. It also means thereview of the system from time to time. The review of the system isdone for:

knowing the full capabilities of the systemknowing the required changes or the additional requirementsstudying the performance

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Information System

is any combination of information technology and people'sactivities that support operations, management and decisionmaking.In a very broad sense, the term information system isfrequently used to refer to the interaction between people,processes, data and technology.is the study of complementary networks of hardware andsoftware that people and organizations use to collect, filter,process, create, and distribute data .an integrated set of components for collecting, storing, andprocessing data and for delivering information , knowledge,and digital products.

http://en.wikipedia.org/wiki/Information_technologyhttp://en.wikipedia.org/wiki/Data_(computing)http://www.britannica.com/EBchecked/topic/287881/information-sciencehttp://www.britannica.com/EBchecked/topic/287881/information-sciencehttp://en.wikipedia.org/wiki/Data_(computing)http://en.wikipedia.org/wiki/Information_technology

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Types of info systems

Executive support system

Decision support systemManagement information systemTransaction Processing system

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Transaction Processing Systems(TPS)

collect, store, modify, and retrieve the transactions of an organization.A transaction is an event that generates or

modifies data that is eventually stored in aninformation system.

http://en.wikipedia.org/wiki/Transaction_processinghttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Transaction_processing

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Management Information Systems(MIS)

provides information that is needed to manageorganizations efficiently and effectivelyManagement information systems involve three

primary resources:-People-Technology

-Information or decision making.

http://en.wikipedia.org/wiki/Information_systemhttp://en.wikipedia.org/wiki/Information_system

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Decision Support Systems(DSS)

is a computer-based information system that supportsbusiness or organizational decision-making activities.DSSs serve the management, operations, and

planning levels of an organization and help to makedecisions, which may be rapidly changing and noteasily specified in advance.

f

http://en.wikipedia.org/wiki/Information_systemhttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Information_system

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Executive Information System(EIS)

is a type of management information system intendedto facilitate and support the information and decision-making needs of senior executives by providing easy

access to both internal and external informationrelevant to meeting the strategic goals of the organization .

http://en.wikipedia.org/wiki/Management_information_systemhttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Organizationhttp://en.wikipedia.org/wiki/Organizationhttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Management_information_system

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Why Do Organizations need InformationSystems?

Computers are essential today. We check our emailwith it, find answers to questions, watch media, bank and more using computers. Therefore, we need

systems that can organize, and serve informationwhen people around the world request it. Servers dothe task. Each website has a server. A computer thathost the website. When you type Google.com the

server who host that website receives data from yourcomputer and sends data back. Letting you access theservers data. Thus you see Google's homepage.Without servers there would be no websites.