| Today, the specification of what makes a system "Unix" is embodied primarily in the POSIX standard, an international standard based on System V and BSD. Commercial Unix systems, such as Solaris from Sun Microsystems, AIX from IBM, and HP-UX from Hewlett Packard, are standard-adhering direct descendants of the original Unix systems. A number of other systems are "spiritual" descendents of Unix, even though they contain none of the original Unix source code. The most notable of these systems is GNU/Linux, which has seen a meteoric rise in popularity. However, a large number of systems derived from the 4.4-BSD-Lite distribution are also popular. All of these systems offer standards compliance and compatibility with SVR4 and earlier versions of BSD. This edition of Unix in a Nutshell attempts to define the cross-section of features and commands that "make a Unix system Unix." To that end, it covers three of the most popular and representative systems now available.
Solaris 10 Solaris 10 is a distributed computing environment from Sun Microsystems. Solaris includes the SunOS 5.10 operating system, plus additional features such as the Common Desktop Environment, GNOME, and Java tools. In addition, the kernel has received significant enhancement to support multiprocessor CPUs, multithreaded processes, kernel-level threads, and dynamic loading of device drivers and other kernel modules. Most of the user-level (and system administration) content comes from SVR4. As a result, Solaris 10 is based on SVR4 but contains additional BSD/SunOS features. To help in the transition from the old (largely BSD-based) SunOS, Solaris provides the BSD/SunOS Compatibility Package and the Binary Compatibility Package. Sun has made binary versions of Solaris for the SPARC and Intel architectures available for "free," for noncommercial use. You pay only for the media, shipping, and handling, or you may download installation CD images. To find out more, see http://www.sun.com/developer. As this book was going to press, Sun announced that it would be making the source code for Solaris available as Open Source. For more details, see http://www.opensolaris.org.
Fedora GNU/Linux There are many distributions of GNU/Linux (the combination of the GNU utilities with the Linux kernel to make a complete operating environment). We have chosen the Fedora Core 3 system from Red Hat, Inc.[*] To find out more, see http://fedora.redhat.com. [*] This is undoubtedly cause to receive hate-mail from the advocates of other distributions. In our defense, we can only claim that it's impossible to cover every GNU/Linux distribution, and that for everyday use with a shell prompt, the systems are all extremely similar.
Mac OS X 10.4 (Tiger) Mac OS X introduced a revolution into the Macintosh world, with a slick new interface (Aqua) running atop a powerful OS kernel based on Mach and FreeBSD. The shell level utilities are largely from FreeBSD. The 10.4 (a.k.a. "Tiger") release is current as of this writing. To find out more, see http://www.apple.com/macosx.
One important "quirk" of Mac OS X is worth noting. The default HPFS filesystem stores filenames in their original case, but it ignores case when looking for files. In practice, this make surprisingly little difference. However, it can occasionally have weird side effects, since things like command completion in the Bash shell are still case-sensitive. |
