UNIX OPERATING SYSTEM

UNIX Operating System

UNIX Operating system

Introduction

It is an operating system (OS) is software that manages the resources of a computer. It is a popular multi-user, multi-tasking OS. UNIX is considered one of the greatest achievements in computer science. It has been around since in the 1960s in various forms, e.g., AIX, SCO UNIX, SUNOS, FreeBSD, Open BSD, Net BSD, Linux, and Mac OS X. Its attributes are stability, portability and security. It is created at Bell Labs by Dennis Ritchie and Ken Thompson (won the ACM Turing Award in 1983). It introduces Multiuser and Multitasking; Toolbox philosophy; Concise syntax and Designed by programmers for programmers. It includes device drivers for computer hardware devices, e.g., graphics cards, network cards, disks. A device driver is a program that allows computer program to interact with hardware devices (Christian & Richter, 1994).

UNIX

It is an operating system of time -sharing, controls the resources of a computer and assigned to users. It allows users to run their programs. It controls devices peripherals connected to the machine. The system is based on a kernel called kernel, which resides permanently in memory, which serves all system calls, manages access to files and the commencement or suspension of user tasks. The UNIX operating system kernel (called the Kernel) is a program written almost entirely in C language, except for one part of interrupt handling, expressed in the language assembler of the processor in which it operates (Clantin, 1993).

The development of UNIX-like systems

UNIX-systems began to appear in the late 1970s and early 1980s. Many proprietary versions, such as Idris (1978), Coherent (1983) and UNIFLEX (1985), were intended to meet the needs of business functionality available to users trained UNIX. UNIX is ??an operating system very popular because it is present on many platforms, from PC to the host (mainframe). The advantage of this is that programs developed on UNIX can be transferred from one platform to another with minimal changes. This system is multitasking, that is to say that he is able to manage and run multiple programs simultaneously. In addition, it is multi-user, that is to say that many people can connect and work together, the system shares then all software and hardware resources of the computer between different users.

The UNIX history is unique in the world of operating systems. Indeed, while most operating systems have been designed by computer manufacturers to sell their machines, UNIX was not designed for commercial purposes. He has become because it is a standard operating system (Christian & Richter, 1994). Unlike a commercial operating system completely controlled by its manufacturer, the UNIX system is now distributed by several speakers including the following major:

AT & T, who is credited with the authorship of Unix;

The University of Berkeley, Unix has evolved in several areas;

SUN Microsystems, to whom we owe the improvements of the GUI;

Santa Cruz Operation and Microsoft, the XENIX / UNIX were the first PC version of UNIX.

Because of this development, the UNIX operating system took several years to be ...