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(*) The UNIX operating System

There have been many operating systems in the past, one at least from each hardware vendor.

They were written in a near-machine language known as ASSEMBLER.

The systems were proprietary(relating to an owner or ownership or (of a product) marketed under and protected by a registered trade name.) because assembler code developed on one machine wouldn't run on another.

Vendors required consumers to purchase expensive proprietary hardware and software if two dissimilar machines needed to talk to each other.

Ken Thompson and Dennis Ritchie changed all that forever. They created UNIX.

This UNIX operating system marks a strong departure from tradition.It has practically everything an operating system should have, but also introduced a number of concepts previously unknown to the computing community.

Beginners with some experience in Windows think of UNIX in terms of it, quite oblivious to the fact that the similarities are only superficial. UNIX is way ahead of other systems in sheer power.

UNIX is not written in assembler but in C

C is a high-level language that was designed with portability considerations in mind which explains why UNIX systems are available on practically every hardware platform.

Apart from handling the basic operating system functions, UNIX offers a host of applications that benefit users, programmers and system administrators .

It encourages users to combine multiple programs to solve a complex problem.

For programmers, UNIX offers a rich set of programming tools that aid in developing, debugging and maintaining programs.

UNIX is also more easily maintained than most systems.

One of these programs is the system's COMMAND INTERPRETER, called the SHELL.

You interact with a   UNIX system through the shell.

Key in a word, and the shell interprets it as a COMMAND to be executed.

A command may already exists on the system as one of several hundred native tools or it could be one written by you.

However , as just mentioned, the power of UNIX lies in combining these commands in the same way the English language lets you combine words to generate a  meaningful idea.

UNIX was written by programmers for their own use, so things that appear obvious to them don't always appear obvious to us.

NOTE : The UNIX system doesn't  offer a fixed set of services. In fact, you have to use your imagination in devising improvised tools from the existing ones. This is what makes UNIX so exciting and challenging







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