Origins of UNIX
UNIX is the name of a group of operating systems that trace their origins back to 1969 at Bell Labs. Since its inception, UNIX was designed to support multiple users and multitasking. UNIX was also one of the first operating systems to include support for Internet networking protocols. The history of UNIX, which now spans over 30 years, is complicated because many companies and organizations have contributed to its development.

UNIX was first written in assembly language, a primitive set of instructions that control the internal instructions of a computer. However, UNIX could only run on a specific type of computer. In 1971, Dennis Ritchie created the C language. In 1973, Ritchie along with fellow Bell Labs programmer Ken Thompson rewrote the UNIX system programs in C language. Because C is a higher-level language, UNIX could be moved or ported to another computer with far less programming effort. The decision to develop this portable operating system proved to be the key to the success of UNIX. During the 1970s, UNIX evolved through the development work of programmers at Bell Labs and several universities, notably the University of California, at Berkeley. -

When UNIX first started to be marketed commercially in the 1980s, it was used to run powerful network servers, not desktop computers. Today, there are dozens of different versions of UNIX, including the following:

• Hewlett Packard UNIX (HP-UX)
• Berkeley Software Design, Inc. (BSD UNIX), which has produced derivatives such as FreeBSD
• Santa Cruz Operation (SCO) UNIX
• Sun Solaris
• IBM UNIX (AIX)

UNIX, in its various forms, continues to advance its position as the reliable, secure OS of choice for mission-critical applications that are crucial to the operation of a business or other organization. UNIX is also tightly integrated with TCP/IP. TCP/IP basically grew out of UNIX because of the need for LAN and WAN communications.

The Sun Microsystems Solaris Operating Environment and its core OS, SunOS, is a high-performance, versatile, 64-bit implementation of UNIX. Solaris runs on a wide variety of computers, from Intel-based personal computers to powerful mainframes and supercomputers. Solaris is currently the most widely used version of UNIX in the world for large networks and Internet websites. Sun is also the developer of the "Write Once, Run Anywhere" Java technology.

Despite the popularity of Microsoft Windows on corporate LANs, much of the Internet runs on powerful UNIX systems. Although UNIX is usually associated with expensive hardware and is no user friendly, recent developments, including the creation of Linux, have changed that image.

Origins of Linux
In 1991, a Finnish student named Linus Torvalds began work on an operating system for an Intel 80386-based computer. Torvalds became frustrated with the state of desktop operating systems, such as DOS, and the expense and licensing issues associated with commercial UNIX. Torvalds set out to develop an operating system that was UNIX-like in its operation but used software code that was open and completely free of charge to all users.

Torvald's work led to a world-wide collaborative effort to develop Linux, an open source operating system that looks and feels like UNIX. By the late 1990s, Linux had become a viable alternative to UNIX on servers and Windows on the desktop. The popularity of Linux on desktop PCs has also contributed to interest in using UNIX distributions, such as FreeBSD and Sun Solaris on the desktop. Versions of Linux can now run on almost any 32-bit processor, including the Intel 80386, Motorola 68000, Alpha, and PowerPC chips.

As with UNIX, there are numerous versions of Linux. Some are free downloads from the web, and others are commercially distributed. The following are a few of the most popular versions of Linux:

• Red Hat Linux – distributed by Red Hat Software
• OpenLinux – distributed by Caldera
• Corel Linux
• Slackware
• Debian GNU/Linux
• SuSE Linux

Linux is one of the most powerful and reliable operating systems in the world today. Because of this, Linux has already made inroads as a platform for power users and in the enterprise server arena. Linux is less often deployed as a corporate desktop operating system. Although graphical user interfaces (GUIs) are available to make Linux user-friendly, most beginning users find Linux more difficult to use than Mac OS or Windows. Currently, many companies, such as Red Hat, SuSE, Corel, and Caldera, are striving to make Linux a viable operating system for the desktop. -

Application support must be considered when Linux is implemented on a desktop system. The number of business productivity applications is limited when compared to Windows. However, some vendors provide Windows emulation software, such as WABI and WINE, which enables many Windows applications to run on Linux. Additionally, companies such as Corel are making Linux versions of their office suites and other popular software packages.

Networking with Linux
Recent distributions of Linux have networking components built in for connecting to a LAN, establishing a dialup connection to the Internet, or other remote network. In fact, TCP/IP is integrated into the Linux kernel instead of being implemented as a separate subsystem.

Some advantages of Linux as a desktop operating system and network client include the following:

• It is a true 32-bit operating system.
• It supports preemptive multitasking and virtual memory.
• The code is open source and thus available for anyone to enhance and improve.