The Rise of Computer Science◦ Machine Language (1st Gen)◦ Assembly Language (2nd Gen)◦ Third Generation Languages (FORTRAN, BASIC,

Java, C++, etc.)◦ CASE (4th Gen)?

IT System Complexity

Systems Analysis & Design

The CHAOS Report (1994) Produced by the Standish Group via surveys, focus groups,

and case studies http://www.standishgroup.com/sample_research/chaos_199

4_1.php Project Resolution Types

◦ Success = On-Time, On-Budget, Fully Featured◦ Challenged = Over-Time, Over-Budget, Fewer Features◦ Impaired = Cancelled

A lot of interesting findings about Software Development track record

The CHAOS Report (1994) Findings

Project Success Factors“The three major reasons

that a project will succeed are user involvement, executive management support, and a clear statement of requirements. There are other success criteria, but with these three elements in place, the chances of success are much greater. Without them, chance of failure increases dramatically.” – The Chaos Report (1994), Standish Group

Project Success Factors% of

Responses

1. User Involvement 15.9%2. Executive Management Support 13.9%3. Clear Statement of Requirements 13.0%4. Proper Planning 9.6%5. Realistic Expectations 8.2%6. Smaller Project Milestones 7.7%7. Competent Staff 7.2%8. Ownership 5.3%9. Clear Vision & Objectives 2.9%10. Hard-Working, Focused Staff 2.4%Other 13.9%

p.3: "Systems analysis and design emerged from the need to perform certain activities around, and particularly prior to, the steps involved in developing a computer system using software engineering tools and techniques."

Systems Analysis & Design

The Cost of Defects

Specification Planning Programming Operation

Cost

of D

efec

ts

A process: a series of steps involving activities, constrains, and resources that produce an intended ouput of some kind

A process involves a set of tools and techniques

Process Defined

Phase I Requirements◦ All balls must remain in motion◦ Only one person at a time can touch a

ball (ball must be passed in the air)◦ Each person may only touch one ball

at a time◦ Juggle for 15 seconds without dropping

the ball Phase II Requirements

◦ All phase I requirements apply◦ The ball cannot be passed to the

person by your side

Juggle Juggle Juggle

Impose consistency and structure on a set of activities

Guide us to understand, control, examine, and improve the activities

Enable us to capture our experiences and pass them along

The Importance of Processes

Capability Maturity Model Integration (CMMI )Carnegie Mellon University

A Practical Example of Process Improvement

Waterfall model V model Prototyping model Operational specification Transformational model Spiral model Phased development: increments and iterations Agile methods

Software Development Process Models or Software Development Life Cycle (SDLC)

One of the first process development models proposed

Works for well understood problems with minimal or no changes in the requirements

Simple and easy to explain to customers It presents

a very high-level view of the development processsequence of process activities

Each major phase is marked by milestones and deliverables (artifacts)

Waterfall Model

Waterfall Model (continued)This version differs from the book but the idea is the same:

There is no iteration in waterfall model Most software developers apply a great

many iterations

Software Process ModelsWaterfall Model (continued)

Provides no guidance on how to handle changes to requirements/design during development (assumes requirements/design can be frozen)

Views software development as manufacturing process rather than as creative process

There is no iterative activities that lead to creating a final product

Long wait before a final product Lacks Business Process Redesign!

Software Process ModelsDrawbacks of The Waterfall Model

Shorter cycle time System delivered in pieces

◦ enables customers to have some functionality while the rest is being developed

Allows two systems functioning in parallel◦ the production system (release n): currently being

used◦ the development system (release n+1): the next

version

Software Process ModelsPhased Development: Increments and Iterations

Software Process ModelsPhased Development: Increments and Iterations(continued)

Incremental development: starts with small functional subsystem and adds functionality with each new release

Iterative development: starts with full system, then changes functionality of each subsystem with each new release

Software Process ModelsPhased Development: Increments and Iterations

Phased development is desirable for several reasons◦ Training can begin early, even though some

functions are missing◦ Markets can be created early for functionality that

has never before been offered◦ Frequent releases allow developers to fix

unanticipated problems globaly and quickly◦ The development team can focus on different areas

of expertise with different releases

Software Process ModelsPhased Development: Increments and Iterations

Emphasis on flexibility in producing software quickly and capably

Agile manifesto http://www.agilemanifesto.org/Value individuals and interactions over process and

toolsPrefer to invest time in producing working software

rather than in producing comprehensive documentation

Focus on customer collaboration rather than contract negotiation

Concentrate on responding to change rather than on creating a plan and then following it

Software Process ModelsAgile Methods

Extreme programming (XP) Crystal: a collection of approaches based

on the notion that every project needs a unique set of policies and conventions

Scrum: 30-day iterations; multiple self-organizing teams; daily “scrum” coordination

Software Process ModelsAgile Methods: Examples of Agile Process

What about process redesign?◦ What does it profit the business if all we do is

automate the process as is?◦ What about COTS?◦ What is the answer?

The Big ?