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CS 634 Information Systems Dr Deepak B Phatak Subrao Nilekani Chair Professor Kanwal Rekhi CS 634 Information Systems Dr Deepak B Phatak Subrao Nilekani Chair Professor Kanwal Rekhi Building, Department of CSE IIT Bombay Session 8, Software Engineering, SRS cs 634 -Session 8, Software Engineering, SRS IIT BOMBAY

SESSION OVERVIEW IIT BOMBAY • • • Principles of Software Engineering Activities Process Maturity SESSION OVERVIEW IIT BOMBAY • • • Principles of Software Engineering Activities Process Maturity Measures Review of ER Model Functional Model • Data Flow Model • User Interface Issues • Software Requirement Specifications (SRS) Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 2

ROLE OF SOFTWARE IIT BOMBAY • Business Functionality Depends Mainly On Software • Good ROLE OF SOFTWARE IIT BOMBAY • Business Functionality Depends Mainly On Software • Good Systems S/W Is The Basis • OS, Programming Languages (3 GL) • Tools To Build S/W Keep Evolving • 4 GL (SQL), RAD Tools • Typical Life Cycle: 10 -15 Years Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 3

Software Characteristics IIT BOMBAY • Software is Developed or Engineered • Not Manufactured • Software Characteristics IIT BOMBAY • Software is Developed or Engineered • Not Manufactured • Software Does Not “Wear Out” • May Become Un-Maintainable • Hardware Does wear out • Most Software is Custom-Built • Limited Role for Packaged Products Which Need Customization and Integration With Other Apps. Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 4

SOFTWARE ENGINEERING IIT BOMBAY • Application of a systematic, disciplined, quantifiable approach to the SOFTWARE ENGINEERING IIT BOMBAY • Application of a systematic, disciplined, quantifiable approach to the development, operation and maintenance of software; i. e. , The application of engineering to software • IEEE Definition 1993 Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 5

SOFTWARE ENGINEERING IIT BOMBAY • Engineering is the analysis, design, construction, verification and management SOFTWARE ENGINEERING IIT BOMBAY • Engineering is the analysis, design, construction, verification and management of technical (or) social entities • To engineer S/W, we must define A development process Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 6

Building Information Systems IIT BOMBAY • Functional Specifications • System Engineering • Feasibility Study Building Information Systems IIT BOMBAY • Functional Specifications • System Engineering • Feasibility Study • Allocation To H/W, S/W, People • • System Analysis System Design Coding, Testing, Integration Acceptance and Deployment Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 7

Software Process Models IIT BOMBAY • Linear Sequential Model • The Waterfall Model • Software Process Models IIT BOMBAY • Linear Sequential Model • The Waterfall Model • User Knows Inadequacies Too Late • Prototyping Model • Model Business, Data, and Processes • Generate Application • Test and Turnover Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 8

Software Process Models IIT BOMBAY • Rapid Application Development • Evolutionary Models • The Software Process Models IIT BOMBAY • Rapid Application Development • Evolutionary Models • The Incremental Model • Sequential + Prototyping • The Spiral Model • Concurrent Development Model • Formal Methods Model Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 9

UMBRELLA ACTIVITIES IIT BOMBAY • • Project Tracking And Control Formal Technical Reviews S/w UMBRELLA ACTIVITIES IIT BOMBAY • • Project Tracking And Control Formal Technical Reviews S/w Quality Assurance Configuration Management Document Production Reusability Management Measurement, Risk management Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 10

Software Project Management IIT BOMBAY • Basic Project Management • Software Teams • Coordination Software Project Management IIT BOMBAY • Basic Project Management • Software Teams • Coordination & Communication • Process and Project Metrics • Based on Lines of Code (Lo. C) • Function Point Oriented • Project Scheduling and Tracking Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 11

Software Engineering IIT BOMBAY • • A Quality Focus Process Methods Tools Dr. Deepak Software Engineering IIT BOMBAY • • A Quality Focus Process Methods Tools Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 12

SEI MODEL IIT BOMBAY • Software Engineering Institute • At Carnegie Mellon University • SEI MODEL IIT BOMBAY • Software Engineering Institute • At Carnegie Mellon University • Capability Maturity Model • Five Levels of Maturity to Measure Effectiveness of an Organization in its Software Development Practices (CMM levels) Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 13

CMM LEVEL 1 (Initial) IIT BOMBAY • Process is Ad Hoc (Even Chaotic) • CMM LEVEL 1 (Initial) IIT BOMBAY • Process is Ad Hoc (Even Chaotic) • Very Few Processes Are Defined • Success Depends Entirely On Individual Efforts Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 14

CMM LEVEL 2 (Repeatable) IIT BOMBAY • Basic Management Processes Are Established • Cost CMM LEVEL 2 (Repeatable) IIT BOMBAY • Basic Management Processes Are Established • Cost Schedule And Functionality Is Tracked • Discipline To Successfully Repeat Projects With Similar Applications Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 15

CMM LEVEL 3 (Defined) IIT BOMBAY • Software process for both management and engineering CMM LEVEL 3 (Defined) IIT BOMBAY • Software process for both management and engineering activities is standardized, documented, and integrated across the organization • All projects use the documented approved version Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 16

CMM LEVEL 4 (Managed) IIT BOMBAY • Detailed measures of process and product quality CMM LEVEL 4 (Managed) IIT BOMBAY • Detailed measures of process and product quality are collected • Process and products quantitatively understood and controlled using detailed measures Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 17

CMM LEVEL 5 (Optimizing) IIT BOMBAY • Quantitative feedback exists from process for continuous CMM LEVEL 5 (Optimizing) IIT BOMBAY • Quantitative feedback exists from process for continuous process improvement • Testing innovative ideas and technologies Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 18

Classical Analysis Modeling IIT BOMBAY • Data Object Description • Entity Relationship Diagram • Classical Analysis Modeling IIT BOMBAY • Data Object Description • Entity Relationship Diagram • Relational Model • Process Specification • Data Flow Diagram • Control Specifications • State Transition Diagram Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 19

SYSTEM ANALYSIS IIT BOMBAY • Represent Information Domain Of The Problem • Which Data, SYSTEM ANALYSIS IIT BOMBAY • Represent Information Domain Of The Problem • Which Data, How Manipulated • Five Ws and One H • Understand S/W Requirements • Specify S/W Functions, Interfaces, Constraints Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 20

ENTITY MODEL IIT BOMBAY shostel sroom scpi sname scourses sroll Student shobbies Dr. Deepak ENTITY MODEL IIT BOMBAY shostel sroom scpi sname scourses sroll Student shobbies Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 21

Course Entity IIT BOMBAY cname ccredits cstudents ccode Course Dr. Deepak B Phatak cs Course Entity IIT BOMBAY cname ccredits cstudents ccode Course Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS cfaculty 22

TABLE REPRESENTATION IIT BOMBAY sroll sname 99011012 Vijay Ambre 01 D 15034 Shaukat Ali TABLE REPRESENTATION IIT BOMBAY sroll sname 99011012 Vijay Ambre 01 D 15034 Shaukat Ali Dr. Deepak B Phatak shostel sroom scpi 02 08 cs 634 -Session 8, Software Engineering, SRS 218 8. 49 7. 94 23

TABLE REPRESENTATION IIT BOMBAY ccode cname CS 634 Information Systems CS 101 Computer Programming TABLE REPRESENTATION IIT BOMBAY ccode cname CS 634 Information Systems CS 101 Computer Programming Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS ccredit 06 06 24

RELATIONSHIPS IIT BOMBAY Student sroll Grade Registers For Course Dr. Deepak B Phatak cs RELATIONSHIPS IIT BOMBAY Student sroll Grade Registers For Course Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS ccode 25

TABLE FOR RELATIONSHIPS IIT BOMBAY sroll ccode grade 99011012 CS 402 AB The REG TABLE FOR RELATIONSHIPS IIT BOMBAY sroll ccode grade 99011012 CS 402 AB The REG Table Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 26

ER MODEL IIT BOMBAY • Captures Static Characteristics • Associations May Be • One ER MODEL IIT BOMBAY • Captures Static Characteristics • Associations May Be • One To One (Shown By A Dot) • One To Many, Many To One • Easy To Map The Structure To Files Or Data Base Schema This Model Does Not Cover Dynamic Features, Workflow, Interfaces, etc. Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 27

DATA DICTIONARY (Entity Sets) IIT BOMBAY • A Repository Of All Information About Entities DATA DICTIONARY (Entity Sets) IIT BOMBAY • A Repository Of All Information About Entities And Associations • For An Entity • • Name, Brief Description Approximate Number in The Set Frequency of Changes Any Other Information Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 28

DATA DICTIONARY (Attributes) IIT BOMBAY • For Each Attribute • • Name, Brief Description DATA DICTIONARY (Attributes) IIT BOMBAY • For Each Attribute • • Name, Brief Description Data Type and Field Width Valid Values (Domain) Typical Values Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 29

FLOW MODELING (DFD) IIT BOMBAY • As information flows through A system, it is FLOW MODELING (DFD) IIT BOMBAY • As information flows through A system, it is transformed • A transformation represents part of a system function • Such flow and the attendant transformation can be captured using a model for data flow • Represented using data flow diagrams Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 30

Example of a Data Flow IIT BOMBAY Reg-form Participant Acct-master Validate Registration Error List Example of a Data Flow IIT BOMBAY Reg-form Participant Acct-master Validate Registration Error List Pnext Roll-list Faculty Enrollment-master Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 31

Example of a Data Flow IIT BOMBAY Reg-form Participant Validate Registration Error List Pnext Example of a Data Flow IIT BOMBAY Reg-form Participant Validate Registration Error List Pnext DF 1 Roll-list Acct-master Validation Information Faculty Enrollment-master Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 32

DFD SYMBOLS IIT BOMBAY External Entity Donor Acct-statement Check Expense Pledge-Info Dr. Deepak B DFD SYMBOLS IIT BOMBAY External Entity Donor Acct-statement Check Expense Pledge-Info Dr. Deepak B Phatak Data Flow Process Data-Store cs 634 -Session 8, Software Engineering, SRS 33

DFD SYMBOLS IIT BOMBAY • External Entity: Source Or Consumer Of Information • Arrow: DFD SYMBOLS IIT BOMBAY • External Entity: Source Or Consumer Of Information • Arrow: Represents Flow of Data • Process: Describes Transformation • Ultimately, Represents the Algorithm or Program That Gets/Puts Data From/To Arrows and Contains Processing Specifications • Store: Stores Data Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 34

DFD Data Dictionary IIT BOMBAY • Each Symbol Must Have An Associated Label • DFD Data Dictionary IIT BOMBAY • Each Symbol Must Have An Associated Label • Data Dictionary Entries Must Define That Label in Terms Of its Meta-Data • Process Narrative (PSPEC) Must be Included Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 35

Example Entries IIT BOMBAY • Reg-Form • Roll Number, Name, Course, Audit/Credit, Time-table slot, Example Entries IIT BOMBAY • Reg-Form • Roll Number, Name, Course, Audit/Credit, Time-table slot, … • Validation-Information • Input to Store: Roll-number • Return From Store • Name, CPI, fees-payment status, … Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 36

CONTEXT DIAGRAM IIT BOMBAY • Called level 0 DFD, or the fundamental system model CONTEXT DIAGRAM IIT BOMBAY • Called level 0 DFD, or the fundamental system model • Single bubble with incoming and outgoing arrows mainly showing the entities involved • Functional partitioning further done to derive several level 1 DFDs Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 37

Context Diagram Example IIT BOMBAY Participant-Info Participant-Grades Course-Info CDEEP SYSTEM Faculty-Info Course Contents Remote-Centre-Info Context Diagram Example IIT BOMBAY Participant-Info Participant-Grades Course-Info CDEEP SYSTEM Faculty-Info Course Contents Remote-Centre-Info Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS Annual Revenue 38

REFINEMENT IIT BOMBAY • Expansion Of a Level 1 DFD To Add Detailed Processes REFINEMENT IIT BOMBAY • Expansion Of a Level 1 DFD To Add Detailed Processes • Flow Continuity Necessary • Expansion Must Have Same I/O Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 39

USER INTERFACE IIT BOMBAY • Modeling Interactive Screens • Capture And Validate Input • USER INTERFACE IIT BOMBAY • Modeling Interactive Screens • Capture And Validate Input • Query Retrieval • Modeling Reports • Contents and Format • On Screen, On Printer • Special Interfaces Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 40

USER INTERFACE IIT BOMBAY • Screen And Forms Layouts • Source And Target Stores USER INTERFACE IIT BOMBAY • Screen And Forms Layouts • Source And Target Stores • Operational Considerations • Ease Of Use (User Friendliness) • Keystroke Minimization Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 41

SRS Document (Draft Contents) IIT BOMBAY • Introduction • Functional Specifications • Data Models SRS Document (Draft Contents) IIT BOMBAY • Introduction • Functional Specifications • Data Models and Data Dictionary • ER Model • Data Flow Model • • • User Interface Requirements Interfaces to Other Systems Procedures and Workflow Acceptance Criteria Appendices Dr. Deepak B Phatak cs 634 -Session 8, Software Engineering, SRS 42