CSC 140: Introduction to IT

1. CSC 140: Introduction to IT Operating Systems CIT 140: Introduction to IT

2. Objectives • To give an overview of the structure of a contemporary system. • To describe briefly the structure and history of the UNIX operating system. • To detain some important system setups. CIT 140: Introduction to IT

3. The Development of the UNIX Operating System • Beginnings • Research Operating System • UNIX Version 1 through UNIX Version 6 • Developed and Written in C • Releases distributed as C Source Code • The design of the system allowed users to run multiple processes concurrently and to connect these processes with streams. • AT& T System V • Released in 1983 • Berkley Software Distributions • 3BSD and 4BSD • The History of Shells • Bourne Shell, C Shell, Korn Shell. • Current and Future Developments - LINUX CIT 140: Introduction to IT

4. CIT 140: Introduction to IT

5. Web Resources CIT 140: Introduction to IT

6. Computer System Hardware • Main/ Primary Storage • Central Processing Unit (CPU) • Disk • Bus • I/O Devices CIT 140: Introduction to IT

7. Computer System Hardware CIT 140: Introduction to IT

8. Main/ Primary Storage • Purpose: To store executing programs or processes. • Also called Volatile Storage place. • Units: bit, byte, KB, MB, GB, TB CIT 140: Introduction to IT

9. CIT 140: Introduction to IT

10. Central Processing Unit (CPU) • CPU executes the programs by fetching them from the RAM, one instruction at a time • Every CPU has its own language called its instruction set • A CPU is functionally divided into two parts • Control Unit • Execution Unit (or Arithmetic and Logic Unit (ALU)) • The storage locations of CPU are called Registers CIT 140: Introduction to IT

11. Disk • A storage place that contains all the computer system’s programs and applications • A nonvolatile storage place • Read and written in terms of sectors and blocks • Latency Time • Seek Time CIT 140: Introduction to IT

12. Bus • A set of parallel wires used to carry information in the form of bits from one sub-system in a computer to another • System Bus • Data Bus, address bus, control bus • Loader Program • Fetch, decode and execute operations form a machine cycle CIT 140: Introduction to IT

13. Machine Cycle CIT 140: Introduction to IT

14. UNIX Software Architecture • Device Driver Layer • Mouse driver, printer driver • The UNIX Kernel • Process Management • File Management • Main Memory Management • Disk Management • The System Call Interface • Entry points to Kernel • Language Libraries • C, C++, Java, FORTRAN etc. • UNIX Shell • Applications • Compilers, word processors, spreadsheets, ftp, telnet, Web browser etc. CIT 140: Introduction to IT

15. UNIX Software Architecture (Contd) CIT 140: Introduction to IT

16. Logging On and Logging Off • Three basic ways of connecting to a UNIX operating system: • Local Area Network Connection • Internet Connection • Stand-alone Connection • <Ctrl-D> CIT 140: Introduction to IT

17. Logging On and Logging Off (Contd) CIT 140: Introduction to IT

18. Correcting Mistakes CIT 140: Introduction to IT

19. Some Important System Setups CIT 140: Introduction to IT