1. Chapter 3 Getting Started

2. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Objectives To give an overview of the structure of a contemporary system To describe briefly the structure of the UNIX operating system To detain some important system setups

3. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Computer System Hardware Main/ Primary Storage Central Processing Unit (CPU) Disk Bus I/O Devices

4. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Computer System Hardware

5. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Main/ Primary Storage Purpose: To store executing programs or processes. Also called Volatile Storage place. Units: bit, byte, KB, MB, GB, TB

6. Copyright © 2005 Pearson Addison-Wesley. All rights reserved.

7. 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

8. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 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

9. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 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

10. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Machine Cycle

11. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. 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.

12. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. UNIX Software Architecture (Contd)

13. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Logging On and Logging Off Three basic ways of connecting to a UNIX operating system: –Local Area Network Connection –Internet Connection –Stand-alone Connection –

14. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Logging On and Logging Off (Contd)

15. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Correcting Mistakes

16. Copyright © 2005 Pearson Addison-Wesley. All rights reserved. Some Important System Setups