1 - architetture software - software as a product

Software as a Product

Paolo Ciancarini

Agenda •  Software products •  The software industry •  Architectural and engineering issues

Why is software important?

•  Software is a key component in the modern industry, especially in the innovative, emerging technologies

•  In the next few slides we report the Gartner hype cycle for the emerging technologies from 2005 to 2010

Hype Cycle of emerging technologies (according to Gartner)

Hype cycles 2005

2006

2007

2008

2009

2010

Discuss

Identify in the Gartner diagrams the technologies which are software-intensive

Software is an industrial product The world sw industry increased its volume at 10% rates yearly

during the ‘90, and at 3% in 2001, now is back at 10% Several technological innovations are based on software (eg. Cellular telephones, Mp3 devices and iTunes, etc.) A cellular telephone includes 5+ MLOC (source Nokia) Windows XP includes 40+ MLOC (Windows 95: 11 MLOC) The developments costs of a software increases with the square of

its dimension in LOC [Berra-Meo 2001]

The software industry

•  According to DataMonitor, the size of the worldwide software industry in 2008 was US$ 303.8 billion, an increase of 6.5% compared to 2007

•  Americas account for 42.6% of the global software market's value

•  In 2013, the global software market will have a value of US$ 457 billion, an increase of 50% since 2008

Software

•  Good: product invisible, intangible, easily duplicated, very expensive to build

•  Component of a computer system: can be widely (re)used (off the shelf) or commissioned by a specific user

•  Abstract machine based on an abstract architecture

•  Service invoked via a well defined interface and based on a communication infrastructure

Software components

•  COTS: “component off the shelf” •  Component based software

architectures •  Building software by integration •  Software component markets

– Enterprise Java Beans – Microsoft .NET

Software: the product of a process

•  Many kinds of software products, many kinds of development processes

•  Study the process to improve the product

•  Examples of processes: waterfall, iterative, agile, extreme,…

•  Software development processes are software too

Many kinds of software

•  Middleware •  Embedded •  Open source •  Web Services •  Mobile (eg. applet) •  Data mining (eg. Search engine) •  Agents •  Social software (eg. Web 2.0) •  Software Ecosystems •  …

Embedded software •  Within only 30 years the amount of software in

cars went from 0 to more than 10,000,000 lines of code

•  More than 2000 individual functions are realized or controlled by software in premium cars, today

•  50-70% of the development costs of the software/hardware systems are software costs

•  (M.Broy, “Challenges in Automotive Software Engineering”, ICSE2006, pp33-42,2006)

Embedded software Code Size Evolution of High End TV Software

24

816

3264

256512

10242048

12000

30004096

32000

100000

64000

1

10

100

1000

10000

100000

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2009

Year of Market Introduction

Kb

ytes

Software as a service Service: the immaterial equivalent of a good •  Software is a service at heart, albeit an automated

one, but it is sold much like a manufactured good. Customers have to pay large sums of money up front, bear much of the risk that a program may not work as promised, and cannot readily switch vendors.

The Economist, 2003

Service oriented architectures •  SOA compose different

services for complementary domains

•  They are often base on stacks of service layers

•  SOA services feature loose coupling that can be “orchestrated” according to some rules of “choreography”

Software ecosystems

•  A software ecosystem is a set of businesses functioning as a unit and interacting with a shared market for software and services, together with relationships supported by a common technological platform

•  Eg: Apple Application Store

Software architecture and engineering

Software architecture •  The discipline of software architecture is centered on

the idea of reducing the design complexity of software systems through abstraction and separation of concerns

•  The discipline has developed a number of design styles and patterns that help in designing or integrating software intensive systems

•  However, it is hard to find sw architects who agree on the right way to architect a software system

•  Wrong decisions in crafting the software architecture are a major cause of project cancellation

Software engineering

•  Software Engineering is a discipline studying the methods to produce software, the theories at their basis, and the tools effective to develop and measure the qualities of software systems

•  Software engineering deals with limited resources •  It is a discipline strongly empirical, that is based

on experience and past projects (“Coloro che non conoscono la storia, sono condannati a ripeterla”)

Main problems

•  Methods to analyze and design a software product •  Architectural and design patterns •  Software development processes and their models •  Software development tools and environments •  Economic issues •  Products and process standards

Producing software is difficult •  Complexity derives from

–  Very fast technical innovation –  Strong international competition –  Psychological issues –  Organizational issues –  Professionals not trained on sw design and

development •  Typical failures: bad project management, wrong

requirements, mediocre design •  Stakeholders with contrasting interests •  New projects start with high risks, scarcely

analyzed

Standish Report 2003

Productivity is low

•  Analyzing 13.522 sw development projects in USA: – 66% out all projects fail (no useful result) – 82% out all projects need more time than

initially planned – 48% out all projects produce products

lacking some function required by the customers

– 55 G$ wasted in one year

Standish : 2004 vs 2009

Caper Jones on sw project failures

•  As to project cancellations, we cover a wider range than Standish Group because they show only IT projects. We include embedded, systems software, web applications, IT, etc. There are some gaps because have no data from the game industry. Our data resembles Standish for IT cancellations, but the embedded and systems worlds are a bit better than the IT world due to more effective quality controls

•  10 function points = 1.86% cancels 100 function points = 3.21% 1000 function points = 10.14% 10000 function points = 31.27% 100000 function points = 47.57%

•  The canceled projects are usually late and over budget when the plug is pulled. On average a canceled project is about 10% more expensive than a successful project of the same size and type

The software process

Stakeholders

Typical stakeholders in a sw process –  Designers –  Management –  Technicians –  Decisors –  Users –  Funding people – …

Each stakeholder has a specific viewpoint on the product and its development process

Process •  Development processes are created and

adapted to different project situations •  Both products and processes can be

evaluated for their quality •  Software needs several different layers of

development process: –  Industrial lifecycle –  Design lifecycle (reqs, build, test) –  Module lifecycle –  Operational lifecycle (eg.: portal)

A history of software processes

The software process •  Software process: set of roles,

activities, and artifacts necessary to create a software product

•  Possible roles: designer, developer, tester, maintenance, ecc.

•  Possible artifacts: source code, executables, specifications, comments, test suite, etc.

Models for the software process

•  Waterfall model (planned, linear) •  Spiral model (planned, iterative) •  Agile model (unplanned, user driven)

4+2 views SCM: sw configuration management, ALM: application lifecycle management

Activities

•  Each organization differs in products it builds and the way it develops them; however, most development processes include: –  Specification –  Design –  Verification and validation –  Evolution

•  The development activities must be modeled to be managed and supported by automatic tools

Mod

els:

pro

cess

dia

gram

Lifecycle differences in the world •  Cusumano in 2003 analyzed 104 sw projects in four areas

India Japan US Europe Total Practice / No. of Projects 24 27 31 22 104 Architectural Specification 83.3% 70.4% 54.8% 72.7% 69.2% Functional Specification 95.8% 92.6% 74.2% 81.8% 85.6% Detailed Design 100.0% 85.2% 32.3% 68.2% 69.2% Code Generation 62.5% 40.7% 51.6% 54.5% 51.9% Design Review 100.0% 100.0% 77.4% 77.3% 88.5% Code Review 95.8% 74.1% 71.0% 81.8% 79.8% Subcycles 79.2% 44.4% 54.8% 86.4% 64.4% Beta Testing 66.7% 66.7% 77.4% 81.8% 73.1% Pair Testing 54.2% 44.4% 35.5% 31.8% 41.3% Pair Programming 58.3% 22.2% 35.5% 27.2% 35.3% Daily Builds

At the Start 16.7% 22.2% 35.5% 9.1% 22.1% In the Build 12.5% 25.9% 29.0% 27.3% 24.0% At the End 29.2% 37.0% 35.5% 40.9% 35.6%

Regression Testing 91.7% 96.3% 71.0% 77.3% 83.7%

(2008)

Productivity differences •  For the same 104 projects Cusumano got the

following data:

India Japan US Europe Total No. of Projects 24 27 31 22 104 LOC/programmer month 209 469 270 436 374 Defects/KLOC (12 mon. after delivery)

0.263 0.020 0.400 0.225 0.150

Software standards

Standards

•  Many institutions define international product or process standards for the global software industry

•  Their goal is usually to improve the quality of software products and their development processes

Software standards

•  Standard IEEE: development methods •  Standard OMG: UML and CORBA •  Standard W3C: Web technologies •  Standard OASIS: Business Process

IEEE Standards on Software •  IEEE 828 - Standard for Glossary of Sw Eng Terminology •  IEEE 830 - Practice for Sw Reqs Specifications •  IEEE 1016 - Practice for Sw Design Descriptions •  IEEE 1012 - Sw Verification and Validation •  IEEE 1062 - Sw Acquisition •  IEEE 1063 - Sw User Documentation •  IEEE 1233 - Developing System Reqs Specifications •  IEEE 12207 - Standard for Sw Life Cycle Processes •  IEEE 1471 - Practice for Architectural Descriptions

www.computer.org/standards!

Summary •  Software is a business, but it is not like other

businesses •  Software products are both the programs and

their documentation, included process documentation

•  A software process is a set of roles and activities to develop a software product

•  Software engineers should use effective tools and methods based on principles scientifically and ethically correct

Self test questions

•  What categories of “software” you know”? •  What are they differences? •  What are the main problems in the

production of software? •  Where can I find a specific paper on a

specific software architecture topic?

References

Textbook: Taylor & Medvidović & Dashofy, Software Architecture: Foundations, Theory, and Practice, Wiley 2009 Additional textbooks: Quian & Fu, Software Architecture and Design Illuminated, Bartlett & Jones 2009 Reekie and McAdam A Software Architecture Primer, 2006

References

Additional textbook on software engineering: Pressman, Software Engineering, McGraw Hill, 6th ed., 2005 Additional textbook on UML: Arlow & Neustadt, UML2 and Unified Process, McGraw Hill, 2007

Journals

(via Internet inside UniBo network): IEEE Transactions on Software Engineering ACM Trans. on Sw Engineering and Methodology IEEE Software IEEE Internet Computing (online) Journal of Object Technology www.jot.fm

scholar.google.com!

Reference web sites

Site of the textbook: www.softwarearchitecturebook.com IASA (int. assoc. of sw architects): www.iasahome.org Major web sites: www.sei.cmu.edu/architecture/!www.handbookofsoftwarearchitecture.com!www.bredemeyer.com! Blogs blog.softwarearchitecture.com!

Questions?