UNIX UNIX is a command line operating system written in the C programming language.

A brief review of UNIX We have been using the UNIX for a while. It is very important to have a big picture about UNIX before we get into more specific UNIX features. The Unix is summarized briefly today.

UNIX UNIX has been around for more than 30 years. That maturity brings a stable, mature high-end operating system available for servers and supercomputers

UNIX UNIX was conceived in the early 1970s by AT&T employees as an operating environment to provide services to software developers who were discouraged by the incompatibility of new computers and the lack of development tools for application development.

UNIX After AT&T was forced to abandon commercial computing as part of an antitrust settlement, AT&T’s UNIX was made available for free to the academic community.

UNIX Because UNIX had been designed in a way that made it easy to “port” (move) to new hardware, colleges and universities that switched to UNIX were able to run a single operating system on all of their computers, even if their computers came from multiple manufacturers.

UNIX Programmers at the University of California at Berkeley made significant modifications to the original source code and called it BSD (Berkeley Software Distribution) UNIX.

UNIX They sent this new version of the UNIX environment to other programmers around the country, who then added tools and code as they saw fit. Possibly the most important advance made to the software by the programmers at Berkeley was the addition of networking software which allowed the operating system to function in a local area network (LAN).

UNIX Sun Microsystems original version of UNIX, the Sun operating system was based on BSD UNIX Version 4.2. At that time, AT&T’s version of the UNIX environment was known as System V. In 1988, Sun OS/BSD, AT&T System 3, and XENIX were combined into what became System V Release 4 (SVR4).

UNIX This new generation of the operating system was an effort to combine the best features of both BSD and AT&T UNIX and create a kind of industry standard for the operating system.

UNIX This enabled software to be developed for UNIX without concern as to whether it was System V or BSD 4.2. The new SVR4 became the basis for not only Sun and AT&T versions of the UNIX environment, but also IBM’s AIX, and Hewlett-Packard’s HP-UX.

UNIX One of the things that UNIX systems are famous for is the interoperability they offer based on what some people have called the universal technical standards and protocols.

UNIX UNIX is particularly desirable as a server platform for client/server computing because of the large range of platform sizes available and the huge base of application and development software available.

UNIX Eventually UNIX spread into the business community, and pushed aside almost all proprietary mainframe and minicomputer operating systems.

UNIX Even IBM and DEC ended up offering their own versions of UNIX as well as their proprietary operating systems.

UNIX UNIX people are pretty fanatical when it comes to support of their favorite operating system, and there is pretty much only one way of doing things—their way or the highway.

UNIX The UNIX file system (UFS) controls the way that information in files and directories is stored on disk and other forms of secondary storage. It controls which users can access what items and how. The file system is therefore one of the most basic tools for enforcing UNIX security on your system.

UNIX A shell is an interface between the user and the kernel. It acts as an interpreter or translator. In other words, the shell accepts commands issued by you, interprets these commands, and executes the appropriate programs.

UNIX Three shells are available in the typical UNIX environment:

UNIX 1) Bourne shell ($) – The default shell for the typical UNIX computing environment. The Bourne shell was developed for the AT&T System V.2 UNIX environment. It is typically used by system administrators.

UNIX 2) Korn shell ($) – A superset of the Bourne shell. It has many of the Bourne shell features plus added features. This is the industry standard for normal system users.

UNIX 3) C shell (%) – A shell based on the C programming language. Like the Korn shell, it has additional features such as aliasing and history. C shell was developed by Sun’s Bill Joy for programmers, but is used with increasing frequency by normal system users.

UNIX

Following are some of the networking advantages that UNIX Servers offer:

UNIX Telnet Administrators can Telnet into a remote host to perform routine administrative tasks. The administrator does not have to be sitting in front of the computer that requires the attention. This is also a cost savings, because a UNIX machine can be operated headless, without a keyboard or a monitor.

UNIX Performance UNIX provides faster read/write operations than other operating systems. UNIX computers tend to operate for months or years without the need of a reboot. Crashes are rare. The number of reboots forced by configuration changes are minimal in a UNIX environment.

UNIX Hardware Because the hardware has a longer life in the UNIX world, more drivers tend to be available and the network cards and other peripherals can be used for a longer period of time. This minimizes the investment in hardware upgrades.

UNIX Automating Processes UNIX/Linux administrators are able to automate many of the processes of the operating system and of the applications by making use of shell scripting. A shell script is a program that the administrator can write to automate certain administrative tasks.

UNIX Scalability Mainstream UNIX systems can take advantage of multiple motherboards that can handle from 2 to over 100 processors. High availability of these systems makes for almost 100% uptime.

UNIX Sun Microsystems was the first company to use a windowing environment in conjunction with the UNIX operating system. In 1993, a consortium of UNIX platform vendors was formed to develop an integrated, standard, and consistent graphical user interface desktop environment.

UNIX Hewlett-Packard, IBM, Novell, and Sun Microsystems, along with many other companies and members of the OSF (Open Software Foundation), X/Open, and the X Consortium all came together to develop the Common Desktop Environment or CDE.

The Common Desktop Environment (CDE): Is a graphical user interface (GUI) between the user and the operating system Provides built-in menus for users to select and run utilities and programs without using Solaris 7 environment commands Enables users to control multiple documents or applications on the screen at the same time Controls activities in windows using both the mouse and the keyboard UNIX

The Common Desktop Environment (CDE) is part of the Common Operating System Environment (COSE, pronounced "cozy") agreement, one of many attempts at unifying the UNIX market. Although COSE itself never took off, CDE has achieved some success-- most notably, all the major UNIX vendors agreeing on the Motif interface as the basis for the Common Desktop Environment.

UNIX Despite its numerous advantages as a desktop and server operating system, UNIX never has been widely accepted in the general corporate world that favors DOS/Windows and Novell's NetWare. A key drawback to UNIX in the corporate arena has been the lack of a single UNIX standard.

UNIX Although Windows dominates the corporate desktop, UNIX is still widely used as a server platform due to its strong performance and robust features. Business-critical servers must be able to deliver high-end features and run the company's transaction-based applications.

UNIX UNIX has a well established position as the operating system of choice for distributed relational databases from vendors like Informix, Ingres, Oracle, and Sybase. Most of these vendors, however, will port their products to Windows NT as well. Any effort to reduce the problems associated with the multiple UNIX variants will do much to bolster the stature of UNIX as a worthwhile alternative to Windows NT.