Software Team Development Software Team Development Practices based on Java Practices based on Java Development Teams at CERNDevelopment Teams at CERN

Rostislav Titov,GS-AIS-EB Section Leader,

CERN

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The reality todayThe reality todayFailure 31.1% of IT projects will be canceled before they ever get

completed 52.7% of projects will cost 189% of their original estimate More than 50% of software projects fail today. 2009: highest failure rate in over a decade!

Success Only 16.2% software projects that are completed on time and

on budget In the large companies only 9% of their projects come in on

time and on budget.

Catastrophe– Ariane 5 (7bn dev, 500 million) – numerical conversion error– Mars Climate Orbiter ($125 million) – metric conversion error– Mars Polar Lander ($165 million) – design error

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Typical FailuresTypical Failures

User requirements not met

Software unreliable

It works great for me, now deploy it for 10,000 users…

Too late (You took so long that our requirements have changed…)

You did what I asked. but I didn’t say what I meant…

Projects completed by the largest American companies have only approximately 42% of the originally proposed features and functions.

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ReasonsReasons Unrealistic Schedules

– Race through the requirements, produce a superficial design and rush into coding.

Changing Requirements During Development

Inappropriate Staffing

Poor-Quality Work – There's a saying about software

quality: “If it doesn't have to work, we can build it really fast.”

Believing in magic– Pitfalls of commercial products

Cheap Good

Fast

Choosetwo

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Project Success factorsProject Success factorsProject Success Factors and % of Responses

1 User Involvement 15.90%

2 Executive Management Support 13.90%3 Clear Statement of Requirements 13.00%4 Proper Planning 9.60%

5 Realistic Expectations 8.20%6 Smaller Project Milestones 0 - 7.7%7 Competent Staff 7.20%8 Ownership 5.30%

9 Clear Vision & Objectives 2.90%10 Hardworking, Focused Staff 2.40%

  Other 13.90%Project Challenged Factors and % of Responses

1 Lack of User Inputs 12.80%2 Incomplete Requirements & Specifications 12.30%

3 Changing Requirements & Specifications 11.80%4 Lack of Executive Support 7.50%

5 Technology Incompetence 7.00%6 Lack of Resources 6.40%7 Unrealistic Expectations 5.90%8 Unclear Objectives 5.30%

  Other 23.00%

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Software Development CycleSoftware Development Cycle

Analysis“Failing to build the right thing”

Design“We didn't have time to do a design."

Implementation“Do you want it on time or documented?”

Test“It's not a bug, it's a feature”

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Requirements AnalysisRequirements Analysis

“Writing software from Requirements is like walking

on water – its easier when frozen”

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AnalysisAnalysis State Goal

“send a man to the moon before end of the decade & return him safely to Earth”, JF Kennedy

Specify the problem not the solution Classification

M MustoS ShouldC Could0W Would

Concept of Operations document “This is my understanding of what you want”

Beware of requirements ‘gold plating’ 80/20 rule Verifiable : use-cases

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Example FailuresExample Failures

Ariane 5 (half billion dollars)

Y2K bug

F-16 & equator

Mars Polar Lander

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Good Design PrinciplesGood Design Principles

Consider alternative approachesNot tunnel vision

Traceable to the requirements Correct & complete

Not reinvent the wheelUse a pattern

Adaptability Accommodate Change

Maximize Cohesion

Minimize Coupling

Understandabilty A design must be understandable if it is to support modification.

“A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away” - Antoine de Saint Exupéry

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Good & Bad designGood & Bad design

Good Design

Change in one part of the system doesn't always require a change in another part of the system.

Every piece of logic has one and one home.

The logic is near the data it operates on.

System can be extended with changes in only one place.

Simplicity

Bad Design

One conceptual change requires changes to many parts of the system.

Logic has to be duplicated.

Cost of a bad design becomes overwhelming.

Can't remember where all the implicitly linked changes have to take place.

Can't add a new function without breaking an existing function.

Complexity

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The Cost of ChangeThe Cost of Change

Cost

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Time

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Lessons LearnedLessons Learned

Should be team workIt’s not always right first time

– Refactoring is OKKeep the vision simpleAutomate repetitive tasksTEST the design

– By modifying the problem

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CodingCoding

“It doesn’t matter if I write poor code… the compiler will tell me if there is problem”

“It doesn’t matter if I make a mistake… it will come out in testing”

• Mars Climate Orbiter ($125 million) metric conversion error

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BugsBugs

Experienced software engineers inject one defect in about every 10 lines of code.

The programmers aren't incompetent or lazy - they're just human.

All humans make mistakes, but in software, these mistakes result in defects.

This means that a modest-size program of 100,000 lines of code typically would start with about 10,000 defects.

Examples : INTEL Pentium : no more than 80-90 BugsCell Phone (200 000 loc) up to 600 errors. Windows-95: 10 Mill. loc: up to 200 000 errors.

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Now imagine you haveNow imagine you have

A multi-domain, multi-lingual horizontal software application

supporting over 15’000 users in 42 countries composed of :

1.5 million Lines of Code

6,000 Java classes

10,000 HTML templates

many other files

Welcome to EDH!

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EDH: Good Old Days (1991-98)EDH: Good Old Days (1991-98)

“Imagination rules the world”

Mac or PC or Unix?C or C++ or ?

University atmosphere

Freedom & Individualism

Choice, choice, choice...

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ResultsResults

Healthy outside, but unhealthy inside

Evolution from freedom to Chaos!Development Platform : Mac, PC & UnixCode : C,C++,Python, Prolog, ProC, PL/SQL, Perl...Comments : Spanish, Italian, French & English...Bugs : “Y2K don’t care”

Obvious code never reviewed : Why would you show your code to anybody? Never did at university... Results count!

Consequence : Maintenance became the primary resource-consuming activity

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The “authoritarian” new days (1998...)The “authoritarian” new days (1998...)

Autocratic– You will use a PC– You will use the chosen IDE– You will use Version Control– You will develop in Java– You will adhere to coding standards– You will show your code to others– You will have to document every change

Production Environment is Sacred– Scheduled Deploys– Team decision, No individual actions– No unreviewed code goes live

Doesn’t sound very motivating?Ironically it is more motivating!

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From University to IndustryFrom University to Industry

Individual Development Practices Team Development Practices

Freedom of Choice for Development Environment

Uniform development environment

Common set of tools

Choice of language & technology Single technology choice

Free selection of tools

Individual Code Responsibility (& blame)

Common Code Ownership (& learning)

... driven by the members of the team

(not management imposed)

Quality of the Product Quality of the Process

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Requires Concrete PracticesRequires Concrete Practices

Code Reviews

Coding Standards

Design Reviews

Mentoring

Uniform development environment

Coherent set of development & deployment tools

Single language & Technology

Test procedures, unit testing & usability studies

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Code Review ExampleCode Review Example

Can you understand the following?

public class ba {

public static final String cur = “USD";

public void dep (int i) { bal -=i; }

public void wit (int i) { bal +=i;}

public String get () { return Integer.toString (bal) + " " + cur }

private int bal;

}

And identify the defect?

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The same codeThe same code

public class BankAccount{ public static final String CURRENCY = “USD"; private int m_balance; public void deposit (int amount) {

balance = balance - amount; } public void withdraw (int amount) {

balance = balance + amount; }

public String getBalance () {

return Integer.toString (bal) + " " + CURRENCY; }}

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Coding Standards – why?Coding Standards – why?Why ? 80% of the lifetime cost of a piece of software goes to

maintenance. Hardly any software is maintained for its whole life by the

original author. Code conventions improve the readability of the software,

allowing engineers to understand new code more quickly and thoroughly.

Cannot review unless you have standards... endless debate – was driving too fast? Cannot answer

without defined speed limits Recommend best practices, avoid bad practices Maintainable & reliable software is key

Produces Common Code Ownership

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Code Reviews - guidelinesCode Reviews - guidelines

Form– Product is guilty until proven innocent – Producer is innocent because he/she is not on

trial – More likely to find bugs if you assume they are

there – Evaluate product not producer – Emphasize "review" aspect; do not "fix it

here". – Raise problems. Do not discuss solutions

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Code Reviews - guidelinesCode Reviews - guidelines

Management Involvement– NONE!– Not a manager's status meeting – Management is not represented during

inspections – Inspections must not be used as a tool to

evaluate workers– … Not a committee, not a working group, not a

status report & not an appraisal instrument …

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BenefitsBenefits

Primary objective – remove defects as early as possible in the development

process

Other benefits : – Early Testing – Project Tracking – Educational – share best practices– Training of new/junior programmers– Improved Communication – Improved Individual Quality– Cross-training– Process-improvement– Shared Responsibility – no individual blame

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The “Yes, buts...”The “Yes, buts...”

I don’t have time for this...

Good programmer’s code doesn’t need reviewing

Its only a ‘minor’ piece of code

Code Changes, then what?– 2nd pair eyes rule– Pair programming

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Coding: ToolsCoding: Tools

Atlassian JIRA

– Issue tracking and project tracking

– EDH: every change must have a JIRA

• Process should be as lightweight as possible

Atlassian GreenHopper

– Agile project management (Scrum)

– EDH: 2-week sprints

Atlassian Confluence

– Documentation (WIKI style)

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Coding: Tools (2)Coding: Tools (2)

Atlassian Crucible

– Online code reviews

– EDH: Every production line of code must be reviewed

Atlassian FishEye

– Browse version control repository (CVS, SVN)

– Real-time notifications of code changes

– Web-based reporting, visualisation and code sharing

Atlassian Bamboo

– Continuous integration

Atlassian Clover

– Java code coverage metrics

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Coding: Tools (3)Coding: Tools (3)

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TestingTestingBugs Standard Software: 25 bugs per 1000 lines of program.

Good Software: 2 errors per 1000 lines. Space Shuttle Software: < 1 errors per 10000 lines.

Example Handy (Cellular Phone): 200 000 lines of program: up to 600 errors.

Windows-95: 10 Mill. lines: up to 200 000 errors.

Sept 24 2004 – Jpeg buffer overrun bug in MS windows

“an attacker who successfully exploited this vulnerability could take complete control of an affected system, including installing programs; viewing, changing, or deleting data; or creating new accounts with full

privileges”

Defects Testing ≠ Debugging

You may have zero bugs, but s/w may not meet requirements, scale, respond-in time…

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TestingTesting Software testing is an art : requires a tester's

creativity, experience and intuition, together with proper techniques.

Most of the testing methods and practices are not very different from 20 years ago.

Testing is more than just debugging.

Testing is expensive. Automation helps.

Complete testing is infeasible. Tradeoff

Testing, while essential, may not be the most effective method to improve software quality.

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What do you test?What do you test?

Correctness testing

Security testing

Reliability testing

Stress testing

Scalability testing

Performance testing

Usability testing

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And after that?And after that?

Software Maintenance 80% of lifetime of software The Legacy Crisis The relative cost for maintaining

software and managing its evolution now represents more than 90% of its total cost.

Example costs– Annual software maintenance cost in USA has

been estimated to be more than $70 billion– Y2K : $8.38 billion US dollar, $90 million for

Nokia 50% of their time is spent in the process of

understanding the code!!!

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Types of MaintenanceTypes of Maintenance

Corrective Maintenance (21%)– A process that includes diagnosis and correction of

errors. Adaptive Maintenance (25%)

– Activity that modifies software to properly interface with a changing environment (hardware and software).

Perfective Maintenance (50%)– Activity for adding new capabilities, modifying existing

functions and making general enhancements. – This accounts for the majority of all effort expended on

maintenance. Preventive Maintenance (4%)

– Activity which changes software to improve future maintainability or reliability or to provide a better basis for future enhancements.

– Still relatively rare.

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Your challenge !Your challenge !

Come in the 9% of projects on time & in budget

Engineer your software (design, review & maintenance in mind)

Control the spiraling IT costs & improve the reputation of the industry

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Thank YouThank You

E-mail:Rostislav.Titov@cern.ch

For More InformationFor More Information

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DesignDesign

One of the things that tools can do is to help bad designers create ghastly

designs much more quickly than they ever could in the past