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UNIX in a Nutshell: System V Edition

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1. Introduction

The Unix operating system originated at AT&T Bell Labs in the early 1970s. System V Release 4 came from USL (Unix System Laboratories) in the late 1980s. Unix source code is currently owned by SCO (the Santa Cruz Operation). Because Unix was able to run on different hardware from different vendors, developers were encouraged to modify Unix and distribute it as their own value-added version. Separate Unix traditions evolved as a result: USL's System V, Berkeley Software Distribution (BSD, from the University of California, Berkeley), Xenix, etc.

1.1 Merging the Traditions

Today, Unix developers have blended the different traditions into a more standard version. (The ongoing work on POSIX, an international standard based on System V and BSD, is influencing this movement.) This quick reference describes two systems that offer what many people consider to be a "more standard" version of Unix: System V Release 4 (SVR4) and Solaris 7.[1 ]

[1] Many other Unix-like systems, such as Linux and those based on 4.4BSD-Lite, also offer standards compliance and compatibility with SVR4 and earlier versions of BSD. Covering them, though, is outside the scope of this book.

SVR4, which was developed jointly by USL (then a division of AT&T) and Sun Microsystems, merged features from BSD and SVR3. This added about two dozen BSD commands (plus some new SVR4 commands) to the basic Unix command set. In addition, SVR4 provides a BSD Compatibility Package, a kind of "second string" command group. This package includes some of the most fundamental BSD commands, and its purpose is to help users of BSD-derived systems make the transition to SVR4.

Solaris 7 is a distributed computing environment from Sun Microsystems. The history of Solaris 7 is more complicated.

Solaris 7 includes the SunOS 5.7 operating system, plus additional features such as the Common Desktop Environment and Java tools. SunOS 5.7, in turn, merges SunOS 4.1 and SVR4. 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 7 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. To find out more, see http://www.sun.com/developer .


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