History of Unix:

• In 1965, Bell Laboratories joined with MIT and General Electric in the development project – Multics.
• In 1969 Ken Thompson, Dennis Ritchie, Rudd Canaday, and Doug McIlroy implemented the first version of the Unix at University of California at Berkley.
• The name UNIX was given by Brian Kernighan.
• In 1989, AT&T and Sun Microsystems joined together and developed system V release 4 (SVR4).
•  Two versions of UNIX that emerged are AT&T Unix and BSD Unix.
•  Two of the main standards mainly in use are POSIX (Portable Operating System Interface) by IEEE and X/open standard. X/Open Company, Ltd. was a consortium founded by several European
• UNIX systems manufacturers in 1984 to identify and promote open standards published its specifications under the name X/open Portability guide( XPG4).
•  Single UNIX Specification (SUSv3) – incorporating IEEE Std 1003.1 and ISO/IEC 9945 and integrating the industry’s Open Systems standards.

Why has Unix been successful?

• Application portability and scalability.
• Open System.
• Underlying operating system source code is available.
• Provides a productive environment.
• Allows multi-tasking and sharing of data.
• Excellent C development environment is built-in.
• Networking capabilities are built in.
• Very important feature of UNIX is that the source code is open , which gives a larger scope for development and debugging.
•  One important advantage that results from the UNIX standard interface is application portability.
• Application portability is the ability of a single application to be executed on various types of computer hardware without being modified.
• This can be achieved if the application uses the UNIX interface to manage its hardware needs.