System Analysis & Design

System Group of components related to each other and work together to achieve a common goal

are collectively called a system.

Characteristics of System

Group of components

Related components

Components work together

Common objectives

Information SystemA system, which collects data from various, sources and processes that data to create

meaning full information for its users.

For Example,

Information office in our college is and information system.

Information department of Sitara Textile is an example of information system.

Computer Based Information

System (CBIS)It is information in which computer plays an important and integral pro. Computer is the

basic components of computer based information system.

Components of computer

based information SystemHardware

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Software

People

Procedure

Database

Hardware The physical components in the information system, which can be touched, are called

hardware.

For Example

Hard disk, monitor, printer etc

SoftwareSet of instruction according to which the computers of information system worked are

collectively called software.

PeoplesThese are most important components in CBIS. People control the overall work of CBIS.

There are different types of peoples work in CBIS.

Programmers

Data Entry Operators

Network Administrator

Database Administrator

System Analyst

ProcedureThere are the rules and regulations, which are followed in the CBIS.

For Example

Examples are Security procedure, backing procedure etc.

Database It is a structure of related data about the organization in which information system is

working. All the data is visually stored in the database. It was not used in older CBIS but

database is not important part of computer based information system of mordner based.

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Management of information

system It is an information system, which collects data from internal and external resources of an

organization and processes that data to fulfill the needs of all the levels of management.

There are four subsystems of MIS.Transaction Processing System (TPS)

Management Information System (MIS)

Decision Support System (DSS)

Office Support System (OSS)

Transaction Processing System (TPS) These systems are used to record day-to-day transaction of an organization. These are

very low-level information system. Sales processing system is a transaction system.

Management Information System (MIS) MRS is the natural extinction to the transaction processing system. These systems get

data from TPS and create reports according the names of different levels of management.

Decision Support System (DSS) DDS also get data from TPS and used it to help decision makers in making their decision.

These systems are just to help decision maker and these system cannot make decision maker.

Office Support System (OSS) These are information system, which provide support in office work like ward processor,

spread sheet etc. These information systems also provide facilities of communication of

information.

Level of managementThere are three types of level, of management.

Upper Level Manager (ULM)

Middle Level Manager (MLM)

Low Level Manager (LLM)

Upper Level Manager (ULM)

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Long-term planner usually plans for lifetime of organization.

Few in numbers

Take decision about the over all work of organization.

There is more risk in their decision-making.

Middle Level Manager (MLM)

Short term planners (plan for month to year of an organization)

Usually are departmental head

Higher manager’s decisions effect their decision

Less risk in their decision

Take both structure and unstructured decision

Usually in reasonable amount.

Low-level managers

Very short term planners (day to month)

Supervision type job

Large in numbers

Higher-level manager’s decisions effect their decision

Usually take structured decision

Less risk involve in their decision

Expert SystemExpert system is software, which work like a human expert & can take decision

according to the certain problems & can also provide helpful suggestions for decision making.

Human experts usually feed their knowledge in expert system & then expert system take decision

by using that knowledge.

Expert system has not general knowledge. Expert system are usually develop for specific

area of interest.

MYCIN is, world’s first Expert System.

For example,

Xcon is an expert system used by DEC (Digital Electronic Corporation) to find the

problem in their computing equipment or computer.

Types of DecisionStructured Decision

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Unstructured Decision

Semi Structured Decision

Structured DecisionThere are predefined decisions we have some formula or rules to take these decisions.

Unstructured DecisionThese are no certain to make these decision but these decisions are only taken by

experience and knowledge.

Semi Structured DecisionThese decisions lie between structured and unstructured decisions. These decision which

have the flavor of the both structured and unstructured. Structured and unstructured are

collectively called semi structured decision.

System Development Life

Cycle It is a step-by-step approach to develop and maintain a system. In development of

information system SDLC is used very successfully now a days.

SDLC was first purposed by national computing center in 1964.

There are 8 stages of SDLC.

Identifying Problem

Feasibility Study

Detail Investigation

System Analysis

System Design

System Development

Testing and Implementations

Review and Maintenance

SDLC is a step-by-step approach but not sequential approach.

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Identifying ProblemIt is the phase in which the problem is identified for which system will be created.

Feasibility StudyIn this stage the problem is checked and analyzed that is their any solution of this

problem. If there is a possible solution according to the situations feasibility of the project exist.

In this phase we study three types of feasibility.

Technical Feasibility

Operational Feasibility

Economic Feasibility

Detail InvestigationIn this phase problems are investigated in detail. In this phase it is checked that what are

the problems and also user requirements are gathered. Usually detail investigation is done by

four methods.

Interviews

Questionnaires

Document Review

Observation

System AnalysisIn this phase different solutions for the problems are analyzed and best possible solutions

chosen in this stage.

System DesignerIn this stage design of a system is created according to the chosen solution. Data flow

diagram, flow charts and entity relationship diagram are created in this phase.

System DevelopmentIn this phase system is developed according to the design. Programs are developed, hard

ware and peoples are selected.

Testing & ImplementationIn this phase system is tested and checked for performance. if it provides planned results

system is implemented.

Review & MaintenanceAfter the implementation of system is review after specific time period for performance.

If there is any problem in working of system is maintained to show desired result in this phase.

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System AnalystProgrammers developed many years back systems and the programmers do all the

investigation and analysis. Programmers were good at programming and they know about

operating and hard ware systems of computers but they are not good enough to understand

business system. So they always get poor information system requirements. So in those days

very few information systems were succeeded and many work disastrous. Then system analyst

came into being. He is a person who is expert in programming and computer technique. But he

also knows business systems very well. He is just like bridge between programmer and business

environment. He is used in nearly all the stages of system development life cycle.

Techniques of System

Investigation There are four method of investigation.

Interviews It is face-to-face communication between interviewer and interviewee.

It is a good way of getting to the point information but it is expensive and time-consuming

method. This method is used when there is a lot of time to investigate and interviewees are

small in numbers. Efficiency of interviews depends upon interviewers.

QuestionnairesIt is less expensive method than interviews but may not provide to the point information. It is

used to investigate to large no of peoples in short time. Efficiencies of questioners depend on

how accurately they are design.

Documents ReviewsIt is the method of examining document exists in a system. Usually this method is used

before taking interviews from the interviewee.

ObservationIt is the method in which system analyst or investigators get users information by observing

their work. It is also used before the interviews and questionnaires.

Data Description TechniquesThere are three types of data description technique.

Data Flow Diagram (DFD)

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Entity Relationship Diagram (ERD)

Flow Charts

Data Flow Diagram (DFD)DFD is used to represent all the data in a system; flow of data from one point to another and

processes applied on the data. DFD is used to describe a system. System analysts communicate

with each other with the help of DFD.

Entity Relationship Diagram (ERD)ERD is usually used to create or describe a database and show entities in a system and

relationship among entities in a graphical form.

Flow Charts Flow charts are used to represent data flow and processes in sequenced form. Usually

system analyst and programmers communicate with each other by using flow charts.

There are three types of flow charts.

Program flow charts.

System flow charts

Run flow charts.

ReportsQueries are very good in getting data from tables or existing queries but queries cannot

show data to the users in user friendly way.

Reports are used for this purpose. Reports can get data from tables or queries and provide

that data to the user in an elegant way. There are three types of reports.

Detail Reports

Summary Reports

Exception Reports

Detail Reports

These are regular reports and created after a specific period of time. In these

reports information is provided in detail.

Summary Reports

It is also regular and time specific reports. It is based on detail report but it

shows information in summaries form like totals.

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Exception ReportsIt is report that is but regular and time specific. It is created when something unusual

happened. Some thing is very good or very bad. It can be created twice in a day or never in a

year.

From,

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