INTRO TO INFORMATION SYSTEMS DEVELOPMENT IS 340 BY CHANDRA S. AMARAVADI 1

OVERVIEW Introduction System defined Characteristics of systems Good systems System development methodologies The Software development life cycle Methods of Analysis Design Design principles 2

INTRODUCTION 3

INTRODUCTION.. Information systems development is primarily concerned with the process of developing the software component of the system. e.g. payroll, inventory, web-based ordering etc. 4

IMPORTANCE OF IS DEVELOPMENT Five million programmers IS needed for business operations One bank has 40,000 programs In many cases, IS -> competitive advantage Most important part of the economy 5

System: any set of related elements (which are under consideration) working together towards the common purpose of transforming inputs into outputs Examples: transportation network, education, building... In the IS context: a system is any part (or whole) of the organization which satisfies the definition above Examples:? 6

system can be open or closed have inputs, processes and outputs have a boundary have subsystems (subsystems share the same characteristics) have a life cycle 7

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How would you view a bank as a system? 9

Prototyping - developing an initial version (model) of the system using quick & dirty techniques and modifying it later. Traditional - go through a structured process of identifying requirements etc. Object oriented – identifies objects and methods. The analysis focusses on identifying object relationships and programming the methods. (not discussed further) 10 SYSTEM DEVELOPMENT METHODOLOGIES

Requirements System User 11 PROTYPING

THE CONVENTIONAL METHOD 12

THE SOFTWARE DEVELOPMENT LIFE CYCLE PLANNING ANALYSIS DESIGN IMPLEMENTATION MAINTENANCE /SUPPORT 13 Systems go through a structured process of development

Traditional Planning/feasibility study - scope and feasibility of the system Analysis - identify & document the requirements Design - develop program/data/user interface structure to meet the requirements Implementation - coding/testing/installation of the program; hiring of programmers/get HW/SW Maintenance/support - keep the system up to date with changes (business [e.g. new accounting methods, new products]; HW/SW; bugs, etc.) 14

15 PLANNING

Interview Employees from top down Identify processes and information classes Process – group of related activities Information class -- collection of information Develop process vs. info class matrix 16

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18 ANOTHER EA MATRIX Adapted from [ County ActivityTractParcelOwnerUnit Land use X Rds & BldgsX TaxationXX Waste disp. Water supply Cons. programs

Gives a broad understanding of processing requirements Can be used as a basis for database design ENTERPRISE ANALYSIS.. 19

METHODS OF ANALYSIS 20

TECHNIQUES OF ANALYSIS: Data Flow Diagramming (DFD) Data modelling Key Performance Indicators (a.k.a. CSFs) ANALYSIS METHODS 21

Cust. Invoice Vendor 1.0 Process order 22 process file data flow external entity

FOR DISCUSSION Classify each of the following as process, external entity data store or information flow: Review inventory A directory of manufacturers The securities and exchange commission Production plan A p.o. forwarded to a manager Verify a P.O. A transcript Sending a loan application Course schedule Prepare balance sheet 23

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DFD GUIDELINES Connect processes first and add other details later Process names must be V+N No restriction on naming of files/external entities Sub-systems must be separate Sub-systems are numbered using the Dewey system (e.g. 1.1, 1.2, 1.3; 1.1.1, 1.1.2…) The total # of inputs and outputs of the subsystem must match with those of its immediate parent 25

BALANCE A RVLE

A technique for identifying information requirements of executives KPIs are critical to the success of the firm KPIs are a.k.a Critical Success Factors (CSFs) 27

KEY PERFORMANCE INDICATORS Identify KPIs key profit & loss items key resources critical processes Identify information measures Note: KPIs are also known as Critical Success Factors 28

29 KPIs FOR A COMPANY LIKE CATERPILLAR key profit & loss items: #orders, order quantities, raw material inventory, finished goods inventory key resources: raw materials, senior engineers critical processes: engineering design; sales & marketing

DISCUSSION With what type of systems are KPIs associated with? 30

DESIGN 31

The purpose of design is to identify a program / interface / data structure to meet the requirements The design technique is referred to as “Transform Analysis” What are the inputs to design? 32

Identify Central Transform (C-T) Dangle DFD from C-T Result is a structure chart a b c fe d 33 (is a design technique)

a bc f. e. d 34

DESIGN PRINCIPLES 35

Coupling Cohesion To design good systems it is necessary to follow design principles 36

Coupling - the extent to which two (or more) modules are interconnected Module A Module BModule A Module B 4 " 37

COUPLING.. Module AModule B Call B Go back to A Go to B 38

Cohesion - the extent to which elements in a module are related Module1 read tax rate compute taxes = tax rate * revenue move taxes to detail line write detail line 39 Module2 write main headings write subheadings write column headings compute taxes = tax rate * revenue

Which of the following are examples of systems?: Motivation, Accounting, Competition, Core competency Do subsystems share the same characteristics as a system? Is KPI an analysis or a design technique? What is the design technique called? During what stage of the SDLC is coding done? What analysis technique is used to identify the information needs of top management? What are some KPIs for a computer manufacturer? What is Enterprise Analysis used for? What sort of benefits can you expect from a good information system? DISCUSSION QUESTIONS 40