What is OpenSource?
OpenSource is software where the source code is open to the public. The source
code, or simly the source, consists of the instructions that are written by the developers
in a programming language of their choice. These files, the source files, are not runable
on the computer, they contain program instructions in plain text.
To make an executable file from these source files we need a compiler. A compiler is a
programm that translates the program instructions in plain text to machine code, the language
that the processor understands directly. These machine instructions are assembeled in a file
that can be executed by the computer, the binary program.
In opposite to OpenSource these source codes are not open to the user in the most cases.
The producers keep them a secret with copyright, only the binary program is delivered to the
users. Hence it is called proprietary software.
OpenSource is going consequently the other way, the source code is free and open to the
user, for reading as well as modifying and testing.
History of the OpenSource Model
The beginning of the OpenSource model took place in 1983 and was caused by Richard
Stallman, a member of MIT (Massachusets Institute of Technology). Unix was widely used in the
universities and the source code was free and open. When the company AT&T restricted
the free usage of the source codes Richard Stallman created the GNU (GNU is Not Unix) project
and founded the Free Software Foundation. The goal was to program a free unix-like operating
system. Free in this case means that it should be obtainable without cost and the source codes
should be open.
The Free Software Foundation decoyed a lot of programmers in a short time and lots of tools
and programs were made. These were built after the original Unix tools, but later they got more
powerful and more stable then the originals.
In the year 1991 Linus Torvalds entered the scene and began to program an own operating
system kernel. He published his work in the internet and soon he found many supporters and
interested workers. This cooperation released a working operating system kernel in 1992.
As before here the motivation arised from dissatisfaction about the commercial products
and the high cost to purchase a commercial operating system.
Originally the term Linux only denominates the operating system kernel. Later on this item
included the utilities and application programs which were and are developed in the internet
community as OpenSource. Until the year 1996 more then one million developers contributed to
the success of Linux and OpenSource.
Copyright - Copyleft
To confront the item of Copyright with Copyleft is a
wordplay by Richard Stallman. In contrast to Copyright licenses the
Copyleft license requires that an
OpenSource software after modification and new release has to be left under this license.
This assures that further developing of OpenSource software cannot become a proprietary
that means the source codes may not become the secret of a producer.
The most important licenses in the domain of OpenSource are
A list of other licenses can be found at the
Free Software Foundation and on the pages of OpenSource.org.
GNU General Public License - GPL
The GPL gives every user the right to copy
distribute the source code. All copies have to contain a disclaimer and a copy of the
The user is also allowed to modify and enlarge the source code and to distribute copies under
the condition that he documents his modifications.
The source code has to be delivered with the product or to be available publicly.
The distributor is allowed explicitely to take fees for the effort of making copies and
demand payment for warranty and support to the customer.
GNU Lesser General Public License - LGPL
The LGPL was originally named
GNU Library General Public License, what directly shows the meaning of this license.
This license covers special features of library programs. In main parts it is identical to
GPL, for libraries the following extensions are made:
A user, who distributes or developes further, has to care that it remains a working library.
The new developement has to stay under the LGPL or may be published under the GPL.
Proprietary software may use OpenSource libraries,
GNU Free Documentation License - GFDL
The GFDL describes the conditions
for documentation for OpenSource software.
Here, too, the free usage and distribution of copies is granted, even in printed form.
As this is a Copyleft license the redistribution has to underlie the GFDL. A special
value is given to the fact of tranparency, that means, that electronic copies should be
delivered in file formats that are easy to be changed. The same should be apllied to
pictures, simple picture processing software shall be able to handle images in OpenSource
documents. New modifications and distributions have to keep a history of the developement
of the document as well as of all authors contributed to a document. An author can demand that
on the outside of the package of a printed document a covertext is applied.
BSD - Berkeley Software Distribution
The license of the Berkeley
Software Distribution is a "Non-Copyleft" license. Modifications and further
developing of the software is granted, but the result of further developement has not to
be published under the same license. In the case of the BSD license it is possible and
already, to change free software to a proprietory product.