World Wide Web relies
heavily on Unix
UNIX, developed by Kenneth Thompson and Dennis Ritchie in 1969 at AT&Tís Bell Labs, is one of the most powerful, versatile, and flexible operating system (OS). It was then revised many times and made commercially available by Interactive Systems Corporation in1977. Its popularity is due to many features including, portability, multi-user environment, and real-time sharing of resources.
The book authored by Sumitabha Das, an electronics engineer from Calcutta University, has been divided into two parts. Part I covers the fundamental concepts of the system useful for the beginners. The intermediate and advanced concepts are explained in the second part. The author has covered Linux also and has discussed a few commands that are different for Linux and Unix.
The beginning of each chapter describes what a reader will learn in that particular chapter and also delves on topics of special interest. In the end of each chapter conclusion, wrap up, and questions for revision are given. Important note, tips and cautions are provided wherever needed.
In Part I, the concepts of Unix Operating System, architecture, commands, utilities, file system, filters have been discussed with examples. For text editing, Unix provides a useful editor i.e. vi editor, which makes use of a number of internal commands. The features of vi editor has been explained in detail in a separate chapter. One of the most important features available in the Unix is the shell. Shell is a command interpreter and a programming language rolled in one. This topic has been discussed at a number of places in the book, which includes shell process and shell programming.
Unix provides multi-user environment. There is a need for proper system administration to maintain the user accounts, security, disk space management and performing backups. These have been explained in the chapter, Essential System Administration. Multi-user environment of this OS facilitates the use of a few communication tools. These could be used to know what others are doing and includes executing commands like finger, talk, mesg and mailx.
Part II covers the advanced concepts, X Window system, TCP/IP networking, the Internet, system programming, advanced system administration and TCP/IP administration.
Like Windows, this OS also provides graphical environment called X Window system that provides client/server-oriented base for displaying windowed graphics. Window manager is the best example. It is an essential component that controls the appearance of window and provides the means by which the user interacts with them. Virtually everything that appears on the screen in X is in a window and a window manager quite simply manages them.
A set of standard protocols that could be used by all machines and networks to communicate is called TCP/IP. TCP/IP is a vendor independent suite of protocols that connects various machines in a network. It is described with the help of four layers of the TCP/IP networking model.
Various freeware and shareware programs available on the Net use Unix for exchange of information. The World Wide Web is the Internetís latest and finest technology service. Large networks and Internet use the Domain Name System (DNS) and details about DNS have been given using a table.
to multiprogramming nature of Unix, multiple processes share a single
resource. If you have some programming experience, you can use your C
knowledge to develop programs and applications to ensure that the
resources are shared in the way they are meant to without conflict. All
aspects of systems programming have been described in the chapters on