{"id":20,"date":"2018-07-12T10:56:56","date_gmt":"2018-07-12T10:56:56","guid":{"rendered":"http:\/\/itp7.epgpbooks.inflibnet.ac.in\/?post_type=chapter&p=20"},"modified":"2022-01-06T11:13:11","modified_gmt":"2022-01-06T11:13:11","slug":"introduction-to-open-source-fsf-history-and-philosophy","status":"publish","type":"chapter","link":"https:\/\/ebooks.inflibnet.ac.in\/itp7\/chapter\/introduction-to-open-source-fsf-history-and-philosophy\/","title":{"rendered":"Introduction to Open Source, FSF, History and Philosophy"},"content":{"raw":"
\"epgp<\/a>\r\n<\/span><\/div>\r\nIntroduction to Open Source, FSF, History and Philosop<\/strong>\r\n\r\n \r\n\r\nIntroduction<\/strong>\r\n\r\n \r\n

In this module, we will get an overview of Open Source software. The role of open source has been appreciated since it has lowered the costs of software and made programming tasks easier. As we are aware, programmers write programs that are intended to execute on some other system. Usually, programmers never give the program code to get executed, they hand over the executable files \/ binary files pertaining to certain application for the purpose of execution. Now, if the end user wants to modify the code, he is not able to do so since the program was created by\u00a0the programmer who has the code. Usually, in organizations, the source code (programs) are not released and it creates vendor lock-in. The end user is bound to approach to the programmer every time he wants the programs to be modified. He cannot approach any other programmer since the source code is with the first programmer who created the software.<\/span><\/p>\r\n

Programmers or Developers write source code. Source code is a collection of computer instructions that will perform certain task. These instructions are written in computer language which is human-readable. Usually, the programs are text files. Figure 1 illustrates a sample program that is written in C language.<\/span><\/p>\r\n \r\n

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Figure 1: Program code of C Language<\/strong><\/p>\r\n \r\n

The program demonstrated in figure 1 is an example of source code. Usually, the source code do not execute directly on computing system, they need compilers to get the code compiled. Once the code is compiled, it generates the object code. The object code can be linked and executed by the system. The source code and object code are like \u201cbefore\u201d and \u201cafter\u201d relationship. The source code is compiled to generate object code. Object code cannot be read by people since it is sequence of bytes. Compiler is a piece of software that is responsible to convert the source code into object code.<\/p>\r\n \r\n\r\n\"\"\r\n

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Figure 2: Process of Compilation<\/strong><\/p>\r\n \r\n

The source code consists of programming language statements that are created by a programmer. Programmers write programs in programming languages like C, C++, Java etc. These\u00a0programming languages provide compilers, the compilers convert programs (source code) into object code, later these object code can be executed by the system.<\/span><\/p>\r\n \r\n

There is another class of languages which do not require a program to be compiled. These languages are called scripting languages. Languages like HTML, Java Script, Shell script, etc. are executed directly by the interpreter. Such programs never get compiled. The interpreter is a piece of software which executes the scripts line by line without converting it into object code.<\/span><\/p>\r\n \r\n\r\n<\/div>\r\n

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Figure 3: Process of Interpretation<\/strong><\/p>\r\n \r\n

A compiled program depends on additional libraries while the scripts are usually set of commands that execute. If a program has a single error, the compiler do not generate object code. A program needs to be re-compiled till the error is solved. Whereas, the interpreters can execute the code line-by-line till them come across the error.<\/p>\r\n \r\n

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Figure 4: Compilation and Interpretation<\/strong><\/p>\r\n \r\n

Figure 2 illustrates the process of compilation and execution and interpretation. It must be observed that although the processes are different, the input is always the source code. It must be noted that in both the cases the source code is different.<\/p>\r\n \r\n\r\nOpen Source Software<\/strong>\r\n\r\n \r\n

Usually, the programmers never give source code to the end users, rather they give the executable file that can run on systems. Source code means the program(s) created by the programmer. This is how, a programmer uses vendor lock-in. Now, whenever the program needs to be modified , the user has to approach programmer every time for modifications. Ultimately, end users must rely on programmers for each and every modification done after providing the software. This is where, open source can come into rescue.<\/p>\r\n \r\n

When we say open source, generally it is meant that along with the executable program, the programmer also delivers source code to the end user. So, if the end user gets the source code, he is relatively free to get the program modified by others if required in future.<\/p>\r\n \r\n

There are two organizations that have provided definition of open source software and free software. The definition of open source is given by Open Source Initiative (OSI). According to the definition, a software is said to be open source if it meets the criteria laid down by OSI. Similarly, there is an another organization which defines free software. If the distribution of source code comply to their norms then the source code is said to be free software. The name of this organization is Free Software Foundation (FSF).<\/p>\r\n \r\n\r\nThere are few terms like FOSS or FLOSS that are related to open source software. The terms are mentioned as below:\r\n