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04/18/23 1
Open Source Software Engineering
Luca Pastorino
04/18/23 2
Summary
Open Source and Free Software Development Process in Open Source Reasons of Open Source Success Corporate Source
04/18/23 3
Summary
Open Source and Free Software Development Process in Open Source Reasons of Open Source Success Corporate Source
04/18/23 4
Free Software / Open Source
Same “enemy” (proprietary software) Are distinct and have different targets Free Software
software must be “free” for social end ethic reasons (not gratis)
users must have freedom1. to run the program2. to study how the program works3. to redistribute copies4. to modify and improve the program
Open Source source code must be open and readable for practical
reasons: it is a development method
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The GNU Project and the Free Software Foundation 1984: initial announcement of the GNU
Project by Richard Stallman Developing a complete UNIX style Operating
System as free software: the GNU (GNU's Not Unix)
1985: Free Software Foundation Promoting the development and use of free
software, particularly the GNU Operating System
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Open Source
1998: Bruce Perens, Eric Raymond and others in the Free software sector, realised that the business world didn’t like the freedom principle associated with it Promote Free software to highlight the many
advantages such as adaptability, reliability, security, standard conformity and indipendence from single companies
Open Source Definition: the fundamental document of the Open Source community
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The Open Source Definition
1. Free Redistribution 2. Source Code Distribution3. Derived Works Allowed4. Integrity of The Author's Source Code5. No Discrimination Against Persons or
Groups 6. No Discrimination Against Fields of
Endeavor 7. License Must Not Restrict Other Software 8. License Must Be Technology-Neutral
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Open Source Products
Operating System Linux BSDs (Berkeley Systems Distribution of Unix)
Internet Apache BIND Mozilla
Programming Tools Perl, Zope and PHP: popular engines behind the "live
content" on the World Wide Web The GNU compilers and tools (GCC, Make and
others): the most powerful, flexible and extensible set of compilers in the world
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Open Source Companies
IBM: Use of Apache to support WebSphere, Eclipse APPLE: Darwin, Quick Time Streaming server HP: Linux on its servers and handhelds SUN: Support Java and Mozilla projects Sharp: Linux on Zaurus handhelds Red Hat Software: Linux distribution Open Source in Government and Non-Profit
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Summary
Open Source and Free Software Development Process in Open Source Reasons of Open Source Success Corporate Source
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A new SE paradigm
Technically, OOS (Open Source Software) is defined in terms of distribution licenses, not developmental methods
Intuitively, the development process supported by OSS promises something new to Software Engineering
The principles of OSS development are showing, in a new way, how complex software systems can be constructed, deployed and evolved
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Taxonomy of Open Source Development The term “Open Source Software development”
is over-loaded There are three major focuses:
Archetype: a high quality program as a reference model (GNU software)
Security: software fault-tolerance (PostgreSQL) Rapidness: rapid adaptation and modification
(Linux, excl. kernel)
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Open Source Communities
Core team
Co-developers
Active User
Passive User
Initiator
Releasecoordinator
.
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Software Engineering Process
The elements of a typical software engineering process are generally enumerated as:
Requirements Analysis System-Level Design Detailed Design Implementation Integration Field Testing Support/Maintenance
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Requirements Analysis
Conventional Software: Create a document
which describes the target customers, their reason for needing this product and the list of features of the product
Open Source Software: Usually Open Source
folks tend to build the tools they need
Use of mailing lists or newsgroups
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System-level Design
Conventional Software: High-level description of
the product, in terms of modules and of the interaction between them
Open Source Software: There usually is no
system-level design The system design is
implicit or it evolves over time
Usually by version 2 or 3 of an open source system, there actually is a system design
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Detailed Design
Conventional Software: Every module defined in
the system-level design is described in detail
The interfaces of each module has to be determined as well as dependencies between modules
Open Source Software: Detailed design ends up
being a side effect of the implementation
Documenting the API is optional and may not occur if the API isn’t intended to be used outside the project
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Implementation
Conventional Software: Every module described
in the detailed design has to be implemented
A module can be considered implemented when it has been created and tested
Open Source Software: This is the fun part The opportunity to write
code is the primary motivation for almost all open source software development efforts
Review is informal No unit test
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Integration
Conventional Software: When all modules are
complete, system-level integration can be done
All modules are compiled, linked and packaged as a system
It usually includes the development of a system-level test
Open Source Software: It involves writing some
man pages, making sure that it builds on every kind of system, writing a Makefile, writing a README, making a tarball, putting it up for anonymous FTP somewhere, and posting a note to a mailing list or newsgroup
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Field Testing
Conventional Software: Field testing usually
begins internally (from employees of the organization)
Then, it will be necessary to run the software esternally (on customers’ computer)
Open Source Software: The best system-level
testing in the industry: users are friendlier when they aren’t charged any money, and power users are more helpful when they can read and fix the source code
Real world experience of real users
“peer review” of hundreds of other programmers
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Support and Maintenance
Conventional Software: Sofware defects are
recorded in a tracking system
These defects are assigned to a software engineer who will propose a change to either the documentation or the implementation
Open Source Software: When a user finds a
bug he can report it an a mailing list, or also send a patch
Sometimes this phase is provided under some payment
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Configuration Management
Conventional change process Change process for OSS
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Summary
Open Source and Free Software Development Process in Open Source Reasons of Open Source Success Corporate Source
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Reasons of Open Source SuccessFrom an end-user perspective: reduces the cost of software acquisition enables diversity simplify collaboration
From a software process and productivity perspective: Enlarging the user community Scalable division of labor Short feedback loops Greater oppotunity for analysis
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Why do developers contribute to Open Source Projects? Personal needs Enjoyment Desire to be part of a team Reputation Money
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Where OS Succeeds and Fails
Successful domains Communities with
unmet software needs Technically
sophisticated user community
General-purpose, commoditized, infrastructure software
Unsuccessful domains Highly vertical domains Highly competitive
domains Highly secure domains High-confidence
domains
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Summary
Open Source and Free Software Development Process in Open Source Reasons of Open Source Success Successful and Unsuccessful Domains Corporate Source
04/18/23 28
Corporate Source: OS Concepts to a Corporate Environment Corporate Source is the application of OS concepts
and methodologies within the corporate envirorment “Open” to all developers behind the firewall Community size is smaller than the Internet
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Why is Corporate Source good? Quality
Programmers write better code for sharing vs. just execution Code Sharing
Corporate Source will promote greater sharing of code among different projects
Maintenance Bugs get fixed faster, and features added faster, if more
people understand and can modify code ‘Bit Rot’ Protection
Prevent code from ‘bit rot’ Intellectual Property
Code is IP that must be protected and widely utilized
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References Open Source Initiative - www.opensource.org GNU project and FSF - www.gnu.org Institute for Software Research -
www.isr.uci.edu/research-open-source.html AICA group - http://linfe.it/ “Open Sources: Voices from the Open Source Revolution”,
edited by DiBona, Ockman, Stone, 1st Edition January 1999 “Understanding the Requirements for Developing Open Source
Software Systems”, Walt Scacchi - Institute for Software Research, University of California, Irvine
“Making Sense of the Bazaar”: 1st Workshop on Open Source Software Engineering” - http://opensource.ucc.ie/icse2001/
“Meeting Challenges and Surviving Success”: 2nd Workshop on Open Source Software Engineering - http://opensource.ucc.ie/icse2002/
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References
“Taking Stock of the Bazaar”: 3rd Workshop on Open Source Software Engineering http://opensource.ucc.ie/icse2003/
“Leveraging Open-Source Communities To Improve the Quality & Performance of Open-Source Software” – Schmidt, Porter (2001)
“Taxonomy of Open Source Software Development” – Nakakoji, Yamamoto (2001)
“Configuration Management for Open Source Software” – Asklund, Bendix (2001)
“Corporate Source: Applaying Open Source Concepts to a Corporate Environment”- Dinkelacker, Garg (2001)
“Why Do Developers Contribute to Open Source Projects? First Evidence of Economic Incentives – Hann, Roberts, Slaughter (2001)