UNIX OPERATING SYSTEM

                         Unix Operating System
Before going to operating system concept we have to know about a language and a package they are very important for and OS development and involvement.

Language:Using language we can create package as well as other application program.
Ex. Java C++.

Package: It is a well defined program used to manipulate the data. 
Ex.Ms- Office.
 Types of Languages 
  Machine level -> Binary language
  Assembly->codes,mnemonic codes,Large No of code.
  High level or procedural ->Programming languages
  such as "C" "JAVA","SAp."...
  NON-procedural-> SQ L(Structured Query
  Language) create tables with out any order and PL SQ L
 Procedural Language/Structured Query Language.
 New language or All Procedural Language->
 clubbing of any 2 languages like C++ "+" visual basic =
 visual studio ++.
*Mnemonic Code* A programming code that is easy to remember because
the codes resemble the original words, such as ADD for addition and SUB for
subtraction.

 

Before going to Unix Operating System first we have to know what does OS meaning.OS has many formal Definitions some of them are given below.

*An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs Source Wikipedia.

*The software that supports a computer's basic functions, such as scheduling tasks, executing applications, and controlling peripherals.

*OS is an interface between user and system's hardware.

 Unix Operating System:-)

• UNIX is a multi-user, multi-tasking operating system. Multiple users may have multiple tasks running simultaneously. This is very different than PC operating systems.

• UNIX is a machine independent operating system. Not specific to just one type of computer hardware. Designed from the beginning to be independent of the computer hardware. 

  *Developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, Michael Lesk and Joe Ossanna.

  *Unix is an operating system that provides a Common User Interface (CUI) for controlling a computer. Thus CUI can run an application that provides a Graphical User Interface (GUI).

  Note*GUI is also called as FUI(Friendly user interface)*

   

  Features of Unix

   >Portability-Runs in any platform.
  >Multi - program.
  >More security-shell is more secure doesn't require Anti
   virus softwares.
  > Email facility.
  > Password settings.

   

  Although there are Different types of os

   

  

   

  Single user:> This operating system is designed to manage the computer so that one user can effectively do one thing at a time.

  Ex.MS-DOS character user interface.

  
  

  Multi-user: A multi-user operating system allows many different users to take advantage of the computer's resources simultaneously. The operating system must make sure that the requirements of the various users are balanced.

  Ex.Unix,Windows

   

  Network Operating systems: The term network operating system, however, is generally reserved for software that enhances a basic operating system by adding networking features.

  Ex. Microsoft Windows Server,Windows NT.

   

  Key Components of Unix 

   

  Kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level.

   

  Shell  A shell is software that provides an interface for users of an operating system to access the services of a kernel.

   

  Different Types of shells is present in Unix.

  • Bourne shell (sh)
  • C shell (csh)
  • TC shell (tcsh)
  • Korn shell (ksh)
  • Bourne Again SHell (bash)