1.12 Open-Source Operating Systems ( For more information on the Flourish conference held at UIC on the subject of Free Libre and Open Source Software , visit ) Open-Source software is published ( sometimes sold ) with the source code, so that anyone can see and optionally modify the code. Open-source SW is often developed and maintained by a small army of loosely connected often unpaid programmers, each working towards the common good. Critics argue that open-source SW can be buggy, but proponents counter that bugs are found and fixed quickly, since there are so many pairs of eyes inspecting all the code. Open-source operating systems are a good resource for studying OS development, since students can examine the source code and even change it and re-compile the changes. 1.12.1 History At one time ( 1950s ) a lot of code was open-source. Later, companies tried to protect the privacy of their code, particularly sensitive issues such as copyright protection algorithms. In 1983 Richard Stallman started the GNU project to produce an open-source UNIX. He later published the GNU Manifesto, arguing that ALL software should be open-source, and founded the Free Software Foundation to promote open-source development. FSF and GNU use the GNU General Public License which essentially states that all users of the software have full rights to copy and change the SW however they wish, so long as anything they distribute further contain the same license agreement. ( Copylefting ) 1.12.2 Linux Developed by Linus Torvalds in Finland in 1991 as the first full operating system developed by GNU. Many different distributions of Linux have evolved from Linus's original, including RedHat, SUSE, Fedora, Debian, Slackware, and Ubuntu, each geared toward a different group of end-users and operating environments. To run Linux on a Windows system using VMware, follow these steps: 1.Download the free "VMware Player" tool from and install it on your system 2.Choose a Linux version from among hundreds of virtual machine images at 3.Boot the virtual machine within VMware Player.
18 1.12.3 BSD UNIX UNIX was originally developed at ATT Bell labs, and the source code made available to computer science students at many universities, including the University of California at Berkeley, UCB. UCB students developed UNIX further, and released their product as BSD UNIX in both binary and source-code format. BSD UNIX is not open-source, however, because a license is still needed from ATT. In spite of various lawsuits, there are now several versions of BSD UNIX, including Free BSD, NetBSD, OpenBSD, and DragonflyBSD The source code is located in /usr/src. The core of the Mac operating system is Darwin, derived from BSD UNIX, and is available at 1.12.4 Solaris Solaris is the UNIX operating system for computers from Sun Microsystems.