History and Features of UNIX

Operating System

• OS can be defined as an organized collection of software consisting of procedures for operating a computer.
• OS provides an environment for execution of programs.
• OS acts as an interface between the user and the hardware of the computer system.

  Operating system continues interacts with user in two ways.

1. Operating system commands
   • Enables user to interact directly with the O.S
2. Operating System calls
   • Provides an interface to a running program and the operating system . system calls in UNIX are written in ‘C’.

History of UNIX

• Ken Thompson at AT & T Bell laboratories designed UNIX in late 1960’s.
• Two versions of UNIX that emerged are AT & T UNIX and BSD Unix.
• In 1989, AT & T and sun Micro Systems joined together and developed system V release 4(SVR 4)
• Two of main standards mainly in use are POSIX and X/open standard. In 1988, MIT formed X consortium developed vendor _ natural X window system.

  What is LINUX ?

• An open source UNIX like operating system.
• Initially created by LINUX Torvalds for pc Architecture ports exit for alpha and space processors
• Developer community world – wide contribute to its enhancement and growth.

Features of UNIX  

• Multi – User , Multi tasking, time sharing
• Portability
• Modularity
• File structure
• Security
• Strong network Supporting & advanced graphics