Overview Software Development. Options. â In-house Development by Computer. Professionals. â In-house Developments b
Information Systems Design & Implementation Issues
Government of India Ministry of Communication & Information Technology Department of Information Technology National Informatics Centre Training Division, New Delhi
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Information System Design & Implementation Issues • What is MIS? • What are MIS Design considerations • Concepts of S/W Engineering • System Development Life Cycle • Structured Methodologies of analysis & Design • System Implementation Issues • End User Perspective 2
What is Management Information System ?
A Management Information System is an organized method by which managers at all levels in the organisation are presented with ? Right Information in ? Right Format in ? Right Time This helps in performing managerial responsibilities of decision making on realistic data. 3
Computerised MIS : Its components • Instructions( Procedures) (that when executed provide desired function and performance) • Data
Structures:
(that enables the programs to adequately manipulate information) • Documents: (that describe the operations and use of the programs)
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Software crisis
• Cost Overruns • Late Delivery • Lack of Reliability • Lack of Users Acceptance
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Overview Software Development Options ?
In -house Development by Computer Professionals
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In -house Developments by End Users
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By contracting to Outside Agencies
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Market Survey and Purchase of Readymade Packages
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Modifications in Readymade Package / already operational package 6
Who should be involved in Development Processes It is a teamwork. The team consists of • User / Customer - Managers - Operating Staff - Those who supply data - Those who receive reports
contd...
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Who should be involved in Development Processes Cont... Computer Professionals - Analyst - Designer - Programmer - Data Entry Operator Note : Many times different roles are played by the same person 8
Software Engineering •
Definition Establishment and use of sound engineering principles in order to obtain a quality software that is economical, reliable, workable and acceptable. S/W Engineering is an outgrowth of hardware & software. It has three key elements
• Methods (Technical how of building a S/W) • Automated or semi automated support tools like - DBMS packages and Present day Visual Tools for applications development etc. - Procedures (to hold the method & tools together )
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Understanding problem
User requirement
Understanding of Analust
Understanding of developer
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1 Recognition of need Review 9 Live Running 8
2 Feasibility Study 3 Analysis
Implementation 7 Testing 6 5 Development
4 Design
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Feasibility Study It comprises of initial investigations of the problem set for the S/W project. It provides one or conceptual solutions. Each conceptual Solution consists of an idea about how the new system will look like. • What will be done on computer and what will be done manually? • What inputs will be needed ? • What outputs will be produced ? • Cost Benefit Analysis?contd.. 12
Feasibility Study It comprises of initial investigations of the problem set for the S/W project. It provides one or conceptual solutions. Each conceptual Solution consists of an idea about how the new system will look like. ? Key questions to be asked are: ? What are the demonstrable need of user? ? Is the problem worth solving? ? How it can be solved with available resources and possible constraints ? What is the cost benefit analysis? Outcome of the feasibility study will be: Redefined required system definition and setting of system boun daries
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Feasibility Study The various alternatives are studied by management from the point of view of • Technical Feasibility • Social Feasibility • Operational Feasibility • Economical Feasibility 14
The Feasibility study is governed by constraints like • Physical Resources • External systems (External Environment) • Overlapping Sub Systems (Internal Environment) • Organizational Goals & Pollicies
For the Selected alternative, terms and conditions are set and the project are defined in clear terms.
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Structured System Analysis
In this stage detailed analysis of new system requirements is done and Structured document of System Requirement Specifications ( SRS) is prepared. The document is prepared with the help of f Technique and graphical tools
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Structured System Analysis ? Key
Questions to be asked are:
- What existing system is doing? - What are the constraints/ problems? - What are the new requirements? - What is the best way of tackling problems / new requirements by reviewing various alternatives? - What are Security / Backup requirements? 17
Strategy of structured Techniques: • Graphical A picture is worth a thousand words
• Separation of Logical ( What) and Physical( How) Views : • Top Down Approach : Getting the big pictures first
• Partitioning : It is not practical to write a single specification for a large system 18
Structured Analysis Tools ? Data
Flow Diagram :
It is a graphical modeling of flow of data within a system and the processing performed on that data Data SourceData Flow Process
Data Flow Destination
Data Store
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Structured Systems Analysis Steps ? Identify
key functions, Data flows( Inputs / Outputs) , Processes, Data stores, sources of inputs and destinations of Outputs etc. ? Draw Context Diagram ? Draw Level 1 Data Flow Diagram
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Technique of Existing System Study There is a saying that “DON’T FIX IT UNTIL YOU UNDERSTAND IT”
So, Find out exactly: • Who does what? • In what manner? • Why that way? • Where it is done? • At what time? • In what order? • At what Cost? 21
contd..
Technique of existing system study With the help of: • Interviews • Questionnaires • Observations • Record Inspection • Sampling 22
Structured Analysis Tools for modeling • Functional Modeling Tools
- Data flow Diagram (DFD) - Functional Decomposition Diagram (FDD) - Control Flow Diagrams - Decision Tables - Decision Trees - Flow Charts - Structured English
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contd..
Structured Analysis Tools for modeling • Data Modeling Tools - Grid chart - Entity-Relationship Diagram (ERD) - Events Life History
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Data Dictionary - Description of process ›› Names of Processes as shown in DFDs ›› Brief Description (Structured English) ›› Processing Logic (Decision tables/Trees) ›› Inputs from the Process ›› Outputs from the Process ›› Access Controls Requirements ›› Audit & Security Requirements contd..25
Data Dictionary - Data Storage files/ Internal Entities ›› Detailed Data Structures
›› Volumetric Information ›› Physical Organization ›› Access Control Requirements ›› Security & Audit Requirements 26
Data Dictionary
- Input / Output Specifications ›› Source
›› Destination ›› List of data items along with format and length ›› Transaction Volume 27
System Design System design is equivalent to preparing blue prints of a building to be constructed giving all details required for the construction activity. Design specifications consist of : ? Tables ? Input Forms ? Output Reports ? Query Designs ? User Interfaces and their linkages ? Flow chart of procedures etc.
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What is an object? ? Object
is something, having certain characteristics, which can be described in real world environment Eg. An Item, A Role, A Report, A Form, An Association, An Organisation etc. ? Any real world activity / system can be divided into inter-linked objects 29
More about Object Each object has attributes (properties) , associated methods ( behavior) and operations, which change the values of attributes, when certain events are triggered As object is instance of a class Eg. A form, A button, List box, Module etc. 30
Model Module 1 Object1
Link
Object2
Module 2
Object1
Function
Module1
Procedure 31
System Design ? Present
day tools help in building prototype of the new system, which can be reviewed by the end user at this stage itself. ? Object Oriented Technology enables further development of programming procedures etc. from the prototype itself. Note : Forms, tables etc. are the objects, to whom properties ( attributes) and methods / Operations can be associated 32
Characteristics of a Good Design • Reliability • Flexibility • Cost Effectiveness • Practicality • Security • Effectiveness • Control • Accuracy • Documentation • Acceptability
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Types of Files • Master
• Transaction • Temporary • Security • Audit • Reference • Backup 34
Files Design Considerations • File size • Normalization • File updation frequency • Media • Acceptable Response (Batch / Online) • Hit rate
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Input Design Input design is the process of converting user originated inputs to a computer based format. • Goal of input design is to make data entry easy Logical and Error free • Menu approach to data entry should be adopted • Input screen design should be automated • Maximum data validation checks should be provided at data entry level itself.
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Ways of Data Entry • Batch mode - Suitable for large volumes of data - Inexpensive - Possibility of errors more significant
•Online Mode - Possibility of errors is less due to immediate online validation - Less fast compared to batch mode - More machines required for data entry
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Output Design Output is the most visible component of computer based Management Information System Objective of an MIS design is to provide right information to right persons in right time. Thus output design needs very careful consideration Information produced must be in a format acceptable to the user.
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Factors affecting output design • Who need it? • In what form? • At what time? • Where is its disposal? • At what cost?
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Types of Reports • Detailed Reports • Summary Reports • History Reports • Job control Reports • Audit Reports
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System Implementation It is fulfill or carrying out of the design specification to put a new information system in operation. Systems Analyst along with the end user is fully involved in this stage of system development life cycle. For successful implementation of the system the following implementation strategy should be adopted.
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System Implementation
• Operating staff involvement • Incremental change • Socio-technical approach
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Stages of system Implementation • Planning
• Installation of Equipment • System Testing with realistic data • Training • Files Conversion • Changeover Strategy • System Strategy • System Review Plans
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Who need Training • All staff of operating Department
• Any other affected staff who either provide data or receive reports • All levels of Managers • Computer room staff 44
Training methods • Lectures
• Discussion • Meeting • On the job training • Training manuals
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How much Training & When to Train • Too much?
• Too less? • Too early? • Too late?
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Change over Considerations • Files Transfer • New Input Forms • New Work Procedures • New Data Collection Methods • New Reporting Formats • New Backup Procedures • New Recovery Procedures 47
Documentation • Terms of Reference • Feasibility Study Report • System Specifications consisting of - Programs Specification - Hardware Specification - Software Maintenance Procedures Manuals - Training Manuals - Operating Procedures Manuals - Clerical Procedures Manuals - Operation Log (History of new system problems 48
Thank You
For further information and suggestions please contact Training Division National Informatics Centre A- block, CGO Complex Lodhi Road, New DelhiDelhi-110003 E-mail:
[email protected] Website: http://training.nic.in
