1. The Web Wizards Guide to Freeware/Shareware Chapter Six Open Source Software

2. Chapter Objectives To explore the concept of open source software and its origins To examine some common misunderstandings about open source software To find out why major commercial software companies are successfully adopting the open source business model To look at the implications of open source software for nonprogrammers

3. What is Source Code? A source code file is the original computer program as it was written by a programmer. A source code file is intelligible to other programmers who know the language in which it is written. Source code is valuable because it shows the logic behind a program, the strategies used for solving various problems, and all the details needed to make the software run.

4. What is Executable Code? An executable file can also be a source code file, but it is usually derived from a source code file using a special program called a compiler. Compiled source code can be executed by a computer, but it is impossible for a human to read and understand. If someone wants to distribute a computer program, but hide the reasoning behind it, they distribute executable files without the corresponding source code.

5. Origins of Open Source Software Other programmers may be able to find and fix bugs in the code. Programmers learn and improve their craft by studying examples of well-written code. Programmers gain recognition and status within the community of programmers by sharing their code. Programmers find it useful to share their source code with one another for many reasons:

6. What is Open Source Software? Anyone can download open source software and modify it as they wish No one can claim proprietary rights to either the original software or any modified versions of the original software Anyone can redistribute their own modifications to open source software as long as they include all their own source code Many software licenses support the basic idea behind open source software (e.g. OSI, GPL):

7. More on Open Source Software Open source software can be distributed as freeware, shareware, or shrink-wrap software. To be successful as a commercial product, a company has to add value to open source software (e.g. superior documentation, customer support, or software updates). Programmers and system administrators have always relied on open source software for many key operations associated with the Internet

8. Proprietary Source Code Proprietary source code is never shared with anyone outside the parent company. If proprietary code slips out, the associated software product is no longer the exclusive property of the parent company. A profitable software product requires proprietary source code The standard business model (e.g. Microsoft) assumes all source code is proprietary:

9. Myths and Misunderstandings Commercial software is always proprietary software If its free, it cant be very good You have to pay for good customer support Open source software is a risky experiment

10. Open Source Success Stories Sendmail (a universally used component of e- mail) Perl (a hugely popular Web programming language) Apache (the most widely used Web server software) Jikes (IBMs Java compiler) Linux (a version of the UNIX operating system for personal computers)

11. Open Source Software and You You benefit from open source software even if you never install an open source program on your computer (consider the success stories on the last slides) The open source business model is a simple solution to the widespread problem of software piracy The availability of open source software ensures a healthy level of competition in the world of commercial software