cse 7315 - sw project management / module 1: process - the framework of sw eng copyright ©...

CSE 7315 - SW Project Management / Module 1: Process - the Framework of SW Eng Copyright © 1995-2006, Dennis J. Frailey, All Rights Reserved CSE7315M01

August 1, 2006 Slide # 1

SMU CSE 7315Planning and Managing a

Software Project

Module 01Process - The Framework for

Software Engineering

Humphrey, chapters 1-2

August 1, 2006

CSE 7315 - SW Project Management / Module 1: Process - the Framework of SW

EngCopyright © 1995-2006, Dennis J. Frailey,

All Rights Reserved

Slide # 2

CSE7315M01

CSE 7315

PLANNING AND MANAGING A SOFTWARE

PROJECT

August 1, 2006



All Rights Reserved

Slide # 3

CSE7315M01

CSE 7315

BUNGLING AND MANGLING A SOFTWARE DISASTER

August 1, 2006



All Rights Reserved

Slide # 4

CSE7315M01

Warning from Dilbert

“If you’re not on a ‘project,’ then you probably have a thankless, boring,

repetitive job. ... But if you are working on a project, life is very different. ...

you spend much of your waking hours fantasizing about how great it would be to have a thankless, boring, repetitive

job.”

Adams, The Dilbert Principle

“If you’re not on a ‘project,’ then you probably have a thankless, boring,

repetitive job. ... But if you are working on a project, life is very different. ...

you spend much of your waking hours fantasizing about how great it would be to have a thankless, boring, repetitive

job.”

Adams, The Dilbert Principle

August 1, 2006



All Rights Reserved

Slide # 5

CSE7315M01

Process - The Framework for Software Engineering

A process is A SET OF TOOLS, METHODS AND PRACTICES used to produce a product.

-- Humphrey, Managing the Software Process

A process is WHAT HAPPENS when you perform a task.

-- Dennis Frailey

August 1, 2006



All Rights Reserved

Slide # 6

CSE7315M01

A Process is Something that Happens Over a Period of

Time• It involves activity– Eg., swimming or walking or computing

• It is dynamic– If it happens twice, that is two different

processes– Or two different instances of the same

process model

• It can be described in words, pictures, diagrams, etc.– The description is called a process model or

description or representation

August 1, 2006



All Rights Reserved

Slide # 7

CSE7315M01

Process Description vs. Process

Computer Program(process

description)

FOR I = 1 TO 10 DO IF A > B THEN CASE J OF ETC ETC ELSE DO SOMETHING ENDIF

Computer in Execution (process)

...

as the computer executes the program, things happen (variables change, data are communicated, devices operate, etc.)

...

August 1, 2006



All Rights Reserved

Slide # 8

CSE7315M01

Uniprocessing

Processor or agent

Program:

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

A process happens when

a processorexecutes aprocess

description

August 1, 2006



All Rights Reserved

Slide # 9

CSE7315M01

MultiprocessingProgram (process model):

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

xxxxxxx

Process # 1

Process # 2

Process # 3

Process # 4

Processor or agent

Processor or agent

Processor or agent

Processor or agent

August 1, 2006



All Rights Reserved

Slide # 10

CSE7315M01

Examples of Processes

Process Description

Computer Program

Roadmap

Recipe

Set of instructions for how to put up wallpaper

Process

Program Execution

Take a Trip

Cook a Meal

Put up Wallpaper

August 1, 2006



All Rights Reserved

Slide # 11

CSE7315M01

Several Interpretations of“Software Process”

A Software Development Process Description is a definition -- it tells you what process to follow when producing software

Executing the Software Development Process is an activity that produces programs

Programs are Computer Process Descriptions which tell the computer what process to follow when executing the program

Executing the Program causes a process to happen and produces some desired outcome

August 1, 2006



All Rights Reserved

Slide # 12

CSE7315M01

A Process has a Beginning and an End in Time

Starting point - when the process starts

.... .... .... something happens .... ....Ending point - when the

process finishes (or it could be

indefinite)

When the process is happening, we say the process is being instantiated or enacted or executed.

August 1, 2006



All Rights Reserved

Slide # 13

CSE7315M01

A Process Description or Model Exists Before And/or After the Process Is Enacted

Process Description (prescriptive) -- What is Supposed to Happen

Wallpaper Hanging

Process Description (descriptive) -- What

Actually Happened

Process (something happens)

August 1, 2006



All Rights Reserved

Slide # 14

CSE7315M01

Process, Methods and Tools

METHODS

Detailed Instructions -- how to do itEg. - Object Oriented Analysis - Structured Walkthroughs

TOOLS

Automation -- do it efficientlyEg. - Compiler, - CASE, - Test Generator, - Measurement Tool

“If you automate without a process, you screw up more efficiently” -- Anonymous

INCREASING KNOWLEDGE

PROCESS (description)Eg. - Design, then Review - Plan Tests with Requirements

A Map -- what to do

August 1, 2006



All Rights Reserved

Slide # 15

CSE7315M01

Why Process is Important Relative to Tools

• Tools without processes or methods are like a fast car with an inexperienced driver – The driver may go fast– But who knows where they will end up?– Wrecks are likely

August 1, 2006



All Rights Reserved

Slide # 16

CSE7315M01

Why Process is ImportantRelative to Methods

• Methods tell you how to do something– like driving lessons or a driving manual

• But methods without processes are like a good driver who doesn’t know where he is -- or where he is going– You may eventually get there– And you may go fast– But you may not get to the right place

very soon

August 1, 2006



All Rights Reserved

Slide # 17

CSE7315M01

Process Gives Knowledge

• Where to go

• How to get there

• Which shortcuts will work

• Which shortcuts will NOT work

• Risks of each option

• Why, not just what

August 1, 2006



All Rights Reserved

Slide # 18

CSE7315M01

How to Describe or Document a Process

It depends on who will use the description and for what purpose

But there are three essential elements of a process description:– Tasks or Activities to be Performed– Artifacts (inputs needed and outputs

produced)– Relationships and Sequences among these

August 1, 2006



All Rights Reserved

Slide # 19

CSE7315M01

Process Descriptions Include ...

• Tasks or Activities -- What to do• Sequencing and Information Flow -- When

to do what • Information or Data (Artifacts)

(compare with a computer program)• Executable Statements• Statement Sequence; Conditional

Statements; Loops; Go To; other Flow of Control constructs

• Data Declarations; Procedure Parameters

August 1, 2006



All Rights Reserved

Slide # 20

CSE7315M01

Optional Information• Additional information depends on the

purpose of the process description

• Examples of additional information include:– Comments and documentation– Entry and/or exit criteria– Why– Who– What and when to measure– Risks– References– ...

August 1, 2006



All Rights Reserved

Slide # 21

CSE7315M01

Representing a Process

• It depends on who will enact the process

Process Description

Agent

Process

August 1, 2006



All Rights Reserved

Slide # 22

CSE7315M01

Alternative Representations

ProcessDescription

ComputerProgram

Roadmap Recipe

Agent Computer Driver Cook

ProcessEnaction

A SpecificInvocationof theProgram

A SpecificTrip

Preparationof A SpecificDish

Data Flow orPetri Nets orEnglish, etc.

SWDeveloper

Developmentof

Software

August 1, 2006



All Rights Reserved

Slide # 23

CSE7315M01

Possible Exam Question

Fill in the chart on the previous page

(assuming some parts are blank)

August 1, 2006



All Rights Reserved

Slide # 24

CSE7315M01

Goals of a Process Representation

• Specific enough to enable a correct outcome– A map should be accurate

• Flexible enough to allow judgment– A good map:• Shows alternate routes• Does not dictate speed, type of car, or other

excessive details that can vary• Does not have to be to scale or precise so long as

it serves its purpose

August 1, 2006



All Rights Reserved

Slide # 25

CSE7315M01

Compare with a Good Recipe

• Specific Enough to enable a correct outcome– Lists all ingredients– Indicates the proper sequence and procedures for

preparing

• Flexible Enough to allow judgment– Allows some variation in ingredients without total

failure– Warns about which steps must be followed

precisely

August 1, 2006



All Rights Reserved

Slide # 26

CSE7315M01

Flexibility vs. Exactness• Staying in the lane without constant

correction (experienced driver vs. novice)

• A computer program needs precise instructions with no room for variation– Because a computer cannot exercise

judgment

• A human being needs a degree of latitude

August 1, 2006



All Rights Reserved

Slide # 27

CSE7315M01

Human Processes Rely on Flexibility

• A process to be executed by humans (such as software development) relies on human judgment– Because of the large number of variables

in the environment and the application• But too much latitude can result in

chaos

August 1, 2006



All Rights Reserved

Slide # 28

CSE7315M01

Why All the Attention to Process?

• Software disasters are costing lots of money and getting more attention as software becomes a larger part of almost every manufactured product

• Process management is being recognized as a core issue behind software development problems

August 1, 2006



All Rights Reserved

Slide # 29

CSE7315M01

Some Types of Software Project Management

Problems• Software development costs more

time/money/resources than anticipated– Business plans new data base for $250K and 9

months– After $2.5 Million and two years, they still

need $1 Million more to complete the job – Program is canceled (1)

(1) McFarlan, F.W. "Portfolio Approach to Information Systems," Harvard Business Review (January, 1974)

August 1, 2006



All Rights Reserved

Slide # 30

CSE7315M01

More Software Project Management Problems

• Software development costs more time/money/resources than it should – Who knows how much it should cost?– Different contractors often give very different

estimates

August 1, 2006



All Rights Reserved

Slide # 31

CSE7315M01

More Problems

• Software fails to meet requirements– System delivers only half of promised

features (functional requirements -- what it is

supposed to do)– CAD system operates so slowly that it is

unusable (performance requirements -- speed, space, etc.) (2)

(2) Frailey, Dennis, Private Communication with CAD system programmers who were fired as a result

August 1, 2006



All Rights Reserved

Slide # 32

CSE7315M01

More Problems

• Fails to meet standards of quality or safety– X-ray machine gives 10,000X dose of

radiation to patient due to faulty software (3)

– Buggy software is constantly crashing– Microsoft Windows calculator has bug in

second digit

(3) ACM/Corporation for Public Broadcasting, "The Machine that Changed the World," (volume 5), PBS

program available on video tape.

August 1, 2006



All Rights Reserved

Slide # 33

CSE7315M01

More Problems• Software causes unanticipated results– Insurance software for claims processing

sends $60M in double payments. 35,000 policy holders quit. (4)

We could go on and on

The basic message is that software must be better managed in order to produce

acceptable products

(4) Rothfeder, Jeffery, "It's Late, Costly, Incompetent - But Try Firing a Computer System." Business Week (November 7,

1988).

August 1, 2006



All Rights Reserved

Slide # 34

CSE7315M01

Software is No Exceptionto the Basic Principles of

Quality Management

• We have learned that process is the proper focus of attention for effective quality improvement

• Although this is NOT a course in quality engineering, we do need to be aware of certain basic principles of quality management

August 1, 2006



All Rights Reserved

Slide # 35

CSE7315M01

Quality Engineering Principle

The quality of a product is determined, in large part, by the

quality of the process used to develop and produce the product.

The quality of a product is determined, in large part, by the

quality of the process used to develop and produce the product.

In other words, if you don’t use a good process you should not be

surprised at poor quality products

August 1, 2006



All Rights Reserved

Slide # 36

CSE7315M01

Quality Management Principle

Consider the process of cooking and the application of these principles.

The way to improve quality is to:- Define (document) the process- Measure and evaluate the

process as it is executed- Improve the process based on

these measurements and evaluations

The way to improve quality is to:- Define (document) the process- Measure and evaluate the

process as it is executed- Improve the process based on

these measurements and evaluations

August 1, 2006



All Rights Reserved

Slide # 37

CSE7315M01

Process Automation Principle

In other words, you must know what process to follow before automating that process.

If you automate the wrong process, you simply do the

wrong thing more efficiently

If you automate the wrong process, you simply do the

wrong thing more efficiently

August 1, 2006



All Rights Reserved

Slide # 38

CSE7315M01

Productivity Principle:

Design the process for real people

Automate the parts that people do not do well.

If you design a process for perfect people, it will

probably fail when executed by normal human beings

If you design a process for perfect people, it will

probably fail when executed by normal human beings

August 1, 2006



All Rights Reserved

Slide # 40

CSE7315M01

Possible Exam Questions Explain why automation alone is not likely to improve a

company’s real productivity and quality

Give an example in the software process where automation is a good idea; give an example where automation does not work very well and people should be charged with doing the job.

August 1, 2006



All Rights Reserved

Slide # 41

CSE7315M01

But .... Software is Not a Manufacturing Process!

• Does this apply to software?• Isn’t software different?

One of the most insidious problems with improving anything is the

PERCEPTION OF UNIQUENESS

Example: almost every small town thinks its sports teams are the best because they are unique

August 1, 2006



All Rights Reserved

Slide # 42

CSE7315M01

But Software Is Differentin Some Ways

• Software does have some special characteristics that must be dealt with

• We will address these in the next module

August 1, 2006



All Rights Reserved

Slide # 43

CSE7315M01

Summary of Module

• Process is central to effective software development

• And to effective management of software development

• Basic principles of quality management apply to software management

cse 7315 - sw project management / module 1: process - the framework of sw eng copyright ©...

Documents