[ADMB Users] Meaning of free software

[Arni Magnusson]

On Thu, 18 Mar 2010, Saang-Yoon wrote:

> Thank you for your response.  Is GCC compiler also free?

Yes, GCC is _more_ free than the Borland compiler. As I see it, software 
comes in four "degrees of freedom":

1. Commercial software. You need to pay money to use the program, or 
commit a crime and steal it.

2. Shareware. Time- and/or feature-limited version of a commercial 
program.

3. Freeware. Not time- and/or feature-limited, but does not allow the user 
to have the source code, modify it, or give other people copies of the 
original or modified program. If the original author decides to make the 
program commercial tomorrow, then it will no longer be available for free 
after that.

4. Free software. Allows the user to have the source code, modify it, and 
give other people copies of the original and modified program. If the 
original author decides to make the program commercial tomorrow, today's 
copy of the source code will still be available for free. This would 
probably result in a group of enthusiasts continuing to maintain and 
develop the program as free software under a different name.

Together, groups 1-3 are called proprietary software, which is the 
opposite of free software. GCC and ADMB are free software. The Borland C++ 
5.5 compiler is somewhere between shareware (does not provide the full 
features of the Borland C++ Builder) and freeware (fully functional 
compiler).

ADMB has traversed the whole ladder. For many years it was commercial 
software and shareware, during 2009 it was freeware, and on 31 Dec 2009 it 
became free software when the full source code was made available.

GCC has been free software since its first release in 1987, and is the 
cornerstone of later free software projects, such as Linux (1994), R 
(2000), Mozilla (2002), and OpenOffice (2002), where years indicate 
version 1.0.

I have nothing against high-quality proprietary software from companies 
like Microsoft, Apple, Adobe, and Oracle that I use all the time. But free 
software is a cooperative and creative approach that enables programs to 
interact in ways no single person or development team could have imagined. 
The approach lends itself particularly well to scientific work, and 
watching R become gradually better than S-Plus has been a convincing 
demonstration that free software is good for science.

Since many of the ADMB core developers work on Linux, testing and 
development tends to focus on the GCC compiler first.

Arni