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  1. 1. Unix Operating System
  2. 2. 1.History 2.Features 3.Clones of Unix 4.Unix kernel 5.Unix file system 6.Why use Unix.? 7.Advantages 8.Disadvantages
  3. 3. History •The Unix OS was developed (based on Multics & CTSS operating systems) by Ken Thompson at the AT&T Bell Laboratories in 1969. •He wanted to create an multi-user operating system to run “space wars” game. •Ken‟s philosophy was to create an operating system with commands or “utilities” that would do one thing well i.e. UNIX
  4. 4. Continue… •The first versions of UNIX were written in “machine-dependent” program (such as PDP-7). •Ken Thompson approached Dennis Ritchie, developer of C language, and in 1973 they compiled UNIX in C to make operating system “portable” to other computers systems.
  5. 5. Features Of Unix •Multi-user and Multitasking OS •Hierarchical file system •The building block approach •Pattern matching (wildcard characters) •Programming facility •Documentation •Unix is said to be an open system. •Most of the servers are on Unix
  6. 6. Clone of UNIX (LINUX) •Red Hat • Calder's • SuSE • Mandrake • Debi an
  7. 7. Unix Kernel •Includes device drivers for computer hardware devices, e.g., graphics cards, network cards, disks •A device driver is a program that allows computer programs to interact with hardware devices •CPU and memory management •File system management •Implements system calls that can be used by •application programs and system utilities
  8. 8. Unix File system •Files contain data, program code, etc •File names cannot have the „/‟ character in them. •Directories Contain files and other directories •Links A link is a pointer reference to another file •Devices Allows applications to access hardware devices
  9. 9. Why Use Unix? •One of the biggest reasons for using Unix is networking capability. •With Unix, networking capability is simply part of the operating system. •Unix is ideal for such things as world wide e-mail and connecting to the Internet. •Unix was written in a machine independent language.
  10. 10. Advantages •Full multitasking with protected memory. •Multiple users can run multiple programs each at the same time. •Very efficient virtual memory •Access controls and security. •Available on a wide variety of machines - the most truly portable operating system. •Unix is a well-stocked toolbox •Unix also provides a stable and secure platform for applications •Do not require direct user interaction with the operating system.
  11. 11. Disadvantages •Designed for the programmer, not the casual user. •Much use of special keyboard characters little typos have unexpected results •Unix is not a very user-friendly operating system •An application program written for one version of UNIX may not run on other versions.
  12. 12. Thank You…