Topic 1- The Basic Knowledge of Open Source and Free Software

Transcription

1 1 Topic 1- The Basic Knowledge of Open Source and Free Software, Reidar Conradi September 1, 2011 Introduction

2 2 What is OSS? Open Source Software: software compliant with one of the licences of Free Software Foundation (1985, or Open Source Initiative (1998, FSF is a non-profit with a worldwide mission to promote computer user freedom and to defend the rights of all free software users. FSF was established by Richard Stallman in 1985 and is located in Boston. The Open Source Initiative (OSI) established by Eric Raymond and Bruce Perens in 1998 is a non-profit corporation formed to educate about and advocate for the benefits of open source and to build bridges among different constituencies in the open-source community.

3 3 Free Software as defined by FSF Free software is a matter of the users' freedom to run, copy, distribute, study, change and improve the software. More precisely, it means that the program's users have the four essential freedoms: The freedom to run the program, for any purpose (freedom 0). The freedom to study how the program works, and change it to make it do what you wish (freedom 1). Access to the source code is a precondition for this. The freedom to redistribute copies so you can help your neighbour (freedom 2). The freedom to distribute copies of your modified versions to others (freedom 3).

4 4 OSI definition of Open Source Open source doesn't just mean access to the source code. The distribution terms of open-source software must comply with the following criteria: 1. Free Redistribution 2. Source Code available 3. Modifications and derived works allowed 4. Integrity of The Author's Source Code

5 5 Continued More on distribution: 5. No discrimination against persons or groups 6. No discrimination against fields of endeavour 7. License attached is the one valid 8. License must not be specific to a product 9. License must not restrict other software 10.License must be technology-neutral Some differences with the FSF definition but most software compliant with one definition is also compliant with the other!

6 6 The OSS phenomenon OSS recently: tsunami ; enabled by the Internet and massive investments by companies. Cross-disciplinarity of social computing and normal SW development: distributed, peer reviews, incremental. Based on launched OSS projects, each with an open community of involved persons. Many licensing models: Strict GPL (contagious copyleft ) vs. generous BSD (any after-use is allowed).

7 7 FS movement vs. OSS movement FS and OSS disagree on the basic principle, but agree more or less on practical recommendations. OSS definition is very close to that of FS. However, OSS is a little looser in some aspects, and have accepted a few licenses that FS considers unacceptably restrictive of the user. The views and values of OSS stem from an attempt of making FS to be more acceptable to business.

8 8 OSS origin and now There are earlier instances of open source and free software such as IBM's source releases of its operating systems and other programs in the 1950s- 60s : DoD/DARPA s development of Arpanet / Internet TCP/IP protocols -- open and distributed work, anti-authoritarian counter culture : Openness spreads via Univ. Berkeley s adaptation of Unix, with built-in Internet protocols and generous BSD licenses with all source provided.

9 9 Continued 1985: Free Software Foundation: by Richard Stallman from MIT AI Lab; ideological CopyLeft -inspired licenses. 1998: Open Software Initiative: by Eric Raymond from IT industry in US, pragmatic BSD-inspired licenses. The Cathedral and the Bazaar. The decision by some people in the free software movement to use the label open source came out of a strategy session held at Palo Alto, California, in reaction to Netscape's January 1998 announcement of a source code release for Navigator.

10 10 Continued 2001: FLOSS (Free/Libre/Open source software) = FSF + OSI; IFIP WG2.13 uses OSS as common denominator. 2000: LAMP platform (Linux, Apache, MySQL, PHP) 3/4 Nordic! 2005: Social computing and creative commons for knowledge work standardized formats for zerocost digital information, the world is flat.

11 11 OSS facts OSS adopted by private and public policy makers: e.g., IBM and Sun Microsystems, IKT-Norge, Skattedirektoratet, KS, Over 50% of Norwegian companies use OSS to make new software, 16% are community members, 6% have themselves gone open. St.meld. 17 ( ) by Norwegian Government recommends OSS and open standards.

12 12 Norwegian initiatives competence center. delingsbazaren.no for distribution of software developed with public money.

13 13 Some well-known OSS projects GNU: GNU (GNU is Not Unix; 1984) is a project that aims on creating a completely free Unix-compatible software system. As of today this project has produced, among lots of other things, widely used compilers and debuggers such as GCC and GDB. The project is run by the Free Software Foundation. Mozilla is the generic name of web-browsers derived from the source code of Netscape Communicator, which Netscape Communications Corp. released at the end of March 1998.

14 14 Linux The development of Linux is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed, both commercially and noncommercially, by anyone under licenses such as the GNU General Public License.

15 15 Starting an open source project An individual who senses the need for a project announces the intent to develop the project in public. The individual may receive offers of help from others. The group may then proceed to work on the code. A developer working on a limited but working codebase, releases it to the public as the first version of an open-source program. The developer continues to work on improving it, and possibly is joined by other developers.

16 16 Continued The source code of a mature project is released to the public, after being developed as proprietary software or in-house software. A well-established open-source project can be forked by an interested outside party. Several developers can then start a new project, whose source code then diverges from the original.

17 17 Market share of F/OSS * Apache is the current #1 web server. GNU/Linux is the #1 server OS on public internet. Sendmail is the leading server. PHP is the web s #1 server-side Scripting language. OpenSSH is the Internet s #1 implementation of the SSH security protocol. * David A. Wheeler: "Why Open Source Software / Free Software (OSS/FS, FLOSS, or FOSS)? Look at the Numbers!, Calibre project, April 2007

18 18 Quality of F/OSS - Scalability GNU/Linux is used in 78% of the world s 500 fastest supercomputers. OSS/FS development processes can scale to develop large software systems. IBM: using GNU/Linux on all machine series, from supercomputer to laptops and mobile devices.

19 19 Quality of F/OSS - Performance GNU/Linux had better performance than Windows for pipes, process, and thread creation. MySQL was quite comparable to the proprietary Oracle database with respect to performance. Microsoft themselves found that Linux and FreeBSD had better performance than Windows by many measures.

20 20 Quality of F/OSS Security The majority of the most serious security problems only apply to Microsoft s products, and not to F/OSS, according to a CERT/CC s report in A 2002 survey of developers found that GNU/Linux are relatively immune from attacks from outsiders. Apache has a better security record than Microsoft s IIS, as measured by reports of serious vulnerabilities.

21 21 Quality of F/OSS- Reliability GNU/Linux is more reliable than Windows NT, according to a 10-month ZDnet experiment. MySQL database had fewer defects than a set of 200 commercial programs used for comparison. Miscroft s IIS Web server have double the time offline (on average) than sites using the Apache software, according to a 3-month Swiss evaluation. 80% of the top ten most reliable hosting providers ran OSS, according to Netcraft s survey in May 2004.

22 22 Total cost of ownership (TCO) of F/OSS vs. Commercial SW OSS/FS costs less to initially acquire. Upgrade/maintenance costs are typically far less. Forrester research found that the average savings on TCO when using OSS/FS database management system is 50% of the commercial ones. TCO of the GNU/Linux is roughly 40% that of Microsoft Windows and only 14% that of the Sun s Solaris.

23 23 F/OSS Licenses

24 24 F/OSS licenses by subject Software licenses: The majority of F/OSS Licenses are applicable to software only. They use terminology and concepts specific for the IT domain. Content licenses: Open Source ideas are also applied to copyrightable subject matter, such as texts, music and other artistic works. Creative Commons is the example. Both: Some licenses, such as Academic Free License (AFL) and the Open Software License (OSL) are neutral with regard to subject matter criterion, as can be applied both to software and content.

25 25 Copyleft and Reciprocity Copyleft is a play on the word copyright created by the authors of the GNU GPL in order to acknowledge a radical departure from traditional software licensing models. The rule of copyleft is that, while redistributing copies of or derivative works from a program, one cannot put restrictions other than imposed by the initial licensor. Some scholars prefer the term reciprocity to the term copyleft in order to emphasize that the fundamental software freedoms are granted to a licensee upon condition that he/she does likewise in case of redistribution of copies or modified version of licensed software.

26 26 F/OSS licenses by degree of freedom Copyleft (or Reciprocal) Licenses GPL is the best example. There is also a distinction between strong and weak copyleft licenses. LGPL is a weak copyleft license. Permissive Licenses Lets anyone to take the work for any purpose, including for creating proprietary programs, without obligation to add anything to said public commons.

27 27 GPL and LGPL The GNU General Public License (GPL): Copyright notice must be attached User can modify the code User can create derivative works User cannot ask money for redistribution of the software code, part or whole User cannot create binary applications, all source code must be distributed with the executable The GNU Library or "Lesser" Public License (LGPL) User can ask money for his/her derivative works User can distribute his/her works in binary

28 28 F/OSS licences by origin Academic Licenses Berkeley Software Distribution (BSD) license, published by University of California, is the first and most popular academic/permissive license. Community licenses originate from popular Open Source communities, generally permissive, such as Apache Software. Companies licenses The first examples of this kind of F/OSS licenses are the Netscape and the Mozilla Public License (MPL). Apple, Sun and Nokia are examples.

29 29 Philosophy of MIT and BSD licenses MIT and BSD licenses are ideal for situations in which you want wide deployment of your ideas and do not care whether this results in open source software or proprietary software.

30 32 Choosing a license Do I agree to open the source code? Do I allow others to modify my source code? Can my program be used with proprietary software? Do I want modifications to be published as open source? Under the same license? Can others merge my code wih closed software?

31 33 Comparison of licenses Licesnse Proprietary Software linking Distribution of the Work Redistributing with changes Compatible with GNU GPL GPL Not allowed Not allowed with not GPL compatible LGPL Allowed Allowed with restrictions Only if the derivative is GNU GPL Only if the derivative is GNU LGPL or GNU GPL BSD Allowed Allowed Allowed The original BSD is not compatible. MIT Allowed Allowed Allowed Yes Yes Yes

32 34 Open standards

33 35 Definitions ITU-T defines it as: standards made available to the general public and are developed (or approved) and maintained via a collaborative and consensus driven process. "Open Standards" facilitate interoperability and data exchange among different products or services and are intended for widespread adoption (2005) Wikipedia: publicly available specifications for achieving a specific task.

34 36 Some main principles Everyone should be free to implement open standards in both proprietary and open source software. Open standards should be available to everyone on royalty-free terms. Open standards should be developed using a collaborative, balanced, and consensus-based approval process. Open standards should be developed under formal and binding commitments for the disclosure and licensing of copyrights and patent claims. Open standards should be made available under reasonable reciprocal licenses that require licensees to share under the same terms their own patent claims reading on the standard. The specifications for open standards should be available to everyone on open source copyright license terms.

35 37 Examples of open standards IP or Internet Protocol for transferring packets of data. HTML (Hypertext Markup Language) and Extensible HTML (XHTML) by W3C for structured hyperlinked document formatting. ODF (Open Document Format) by OASIS for office document formats.