3.3 An Environment of Programs

Programming is an exercise in problem solving. It's an iterative, gradual process. Although it can be done by one person alone, it's often a social activity (this surprises many newcomers). It requires developing specific problem-solving skills and learning a few tools. Programming is sometimes tricky and can be frustrating. On the other hand, for those with an aptitude, there's a great sense of satisfaction that comes from building a working program.

Computer programs can be many things, from barely useful, to aesthetically and intellectually stimulating, to important generators of new knowledge. They can be beautiful. (They can also be destructive, stupid, silly, or vicious; they are human creations, after all.) Because writing a program is an iterative, building, gradual process, there can be real satisfaction in seeing the work unfold from simple beginnings to complete structures. For the beginning student, this gradual unfolding of a new program mirrors the gradual mastery of the language.

As our culture began writing and accumulating programs in the middle of the 20th century, a programming environment began to develop. Gradually, we've been accumulating a substantial body of procedural knowledge. Programs often reflect the fact that they swim in waters populated by many other programs, and beginning programmers can expect to learn a lot from this environment.

3.3.1 Open Source Programs

As programming has become important in the world, it has also become economically valuable. As a result, the source code for many programs is kept hidden to protect commercial assets and stymie the competition.

However, the source code for many of the best and most used programs are freely available for anyone to examine. Freely available source code is called open source. (There are various kinds of copyrights that may attach to open source program code, but they all allow anyone to examine the source code.) The open source movement treats program source code in a similar manner to the way scientists publish their results: publicly and open to unfettered examination and discussion.

The source code for these programs can be a wonderful place for the beginning programmer to learn how professional programmers write. The programs available in open source include the Perl interpreter and a large amount of Perl code, the Linux operating system, the Apache web server, the Netscape web browser, the sendmail mail transfer agent, and much more.