Answers to Exercises 1. What is free software? List three characteristics of free software. “Free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech,” not as in “free beer.” —Richard Stallman (page 2) Four freedoms characterize free software (www.gnu.org/philosophy/free-sw.html): a. The freedom to run the program for any purpose (freedom 0). b. The freedom to study how the program works and to adapt it to your needs (freedom 1). Access to the source code is a precondition for this freedom. c. The freedom to redistribute copies so you can help your neighbor (freedom 2). d. The freedom to improve the program and to release your improvements to the public so that the entire community benefits (freedom 3). Access to the source code is a precondition for this freedom. 2. Why is Linux popular? Why is it popular in academia? Linux is portable, is based on standards, is written in C, has a kernel programming interface, can support many users, and can run multiple tasks simultaneously. For more information refer to “What Is So Good About Linux?” on page 6. The source code for the operating system is readily available so students can understand more easily how Linux works and can modify the code further to understand its operation and change the way it works. For more information refer to “The Code Is Free” on page 5.