The layout location of these items can be customized, but the term used for each of them remains the same. The menu panel stretches across the top of the screen. It contains three menus and a number of default icons that start software applications. It also provides a clock, volume control applet, and a notification area. The desktop area is the screen space between the menu panel and the window list panel. The Computer, Home Directory, and Trash icons are located in the top left corner of this area. Those users more familiar with Microsoft Windows may equate these icons to the My Computer, My Documents, and Recycle Bin, respectively. The window list panel is located at the bottom of the screen. It features the Show Desktop icon, running applications as icons, and it gives access to the workplace switcher and the trash.

INTRODUCTION TO LINUX Presented by: Neha Linus Torvalds Creator of Linux:

Objectives History GNU Project Beginning of Linux Features Linux Pros and Cons Architecture Applications

History In 80’s, Microsoft’s DOS was the dominated OS for PC. Apple MAC was better, but expensive. UNIX was much better, but much, much more expensive. Only for minicomputer for commercial applications. People were looking for a UNIX based system, which is cheaper, user friendly and could run on PC. DOS, MAC and UNIX were proprietary, i.e., the source code of their kernel is protected. No modification is possible without paying high license fees.

GNU project Established in 1984 by Richard Stallman GNU is a recursive acronym for “GNU's Not Unix” Aim at developing a complete Unix-like operating system which is free for copying and modification Companies make their money by maintaining and distributing the software, e.g. optimally packaging the software with different tools (Redhat, Slackware, Mandrake, SuSE, etc) Stallman built the first free GNU C Compiler in 1991.

Beginning of Linux A famous professor Andrew Tanenbaum developed Minix, a simplified version of UNIX that runs on PC. Minix was for class teaching only. No intention for commercial use. In Sept 1991, Linus Torvalds, a second year student of Computer Science at the University of Helsinki, developed the preliminary kernel of Linux, known as Linux version 0.0.1

Features Free Compatibility on most hardware Well documented Customisable Open source Multi-tasking capability TCP/IP Networking High level of security Stable, reliable operating system Support for running web servers such as ‘Apache’, to run application protocols such as FTP

Advantages over Windows It's almost free to relatively inexpensive. Source code is included. Bugs are fixed quickly and help is readily available through the vast support in Internet. Linux is more stable than Windows. Linux is truly multi-user and multi-tasking Linux runs on equipment that other operating systems consider too underpowered, e.g. 386 systems, PDA, etc Linux Pros and Cons

Linux Pros and Cons Disadvantages compared with Windows My program cannot run on Linux Isn't as popular as Windows No one commercial company is responsible for linux. Linux is relatively hard to install, learn and use. The myth of "user-friendly"

What’s so special about Linux?

Growing and growing… At the end of 1992 there were about a hundred Linux developers. Next year there were 1000. And the numbers multiplied every year. Linux: No of Users

Architecture KERNEL TO SHELL COMMUNICATION KERNEL TO HARDWARE COMMUNICATION HARDWARE SHELL Tools and Application SHELL SHELL SHELL KERNEL

Architecture contd..

Linux shell Shell interprets the command and request service from kernel. Similar to DOS but DOS has only one set of interface while Linux can select different shell. Bourne Again shell (Bash), TC shell (Tcsh), Z shell (Zsh). Bash is the default for Linux.

Application User’s Interface Comprise a set of functions (often known as API) that can be used by the applications and library routines to use the services provided by the kernel. System call interface Interface between the kernel and user. Allow user to make commands to the system. Divided into text based and graphical based. The part of an OS where the real work is done Kernel

Default Fedora Desktop The default desktop has three distinct areas. From top to bottom, the areas are: The menu panel The desktop area The window list panel

Shells & GUIs Linux supports two forms of command input. through textual command line shells similar to those found on most UNIX systems (e.g. sh – the Bourne shell, bash the Bourne again shell and csh – the C shell) . through graphical interfaces (GUIs) such as the KDE, GNOME window managers

Kernel Kernel is the core of Linux Os (Operating System). It acts as an intermediary between the computer hardware and various programs/application/shell. The Linux kernel includes: device driver support for a large number of PC hardware devices (graphics cards, network cards, hard disks etc.) advanced processor and memory management features support for many different types of file systems (including DOS floppies and the ISO9660 standard for CDROMs).

Features of Kernel Process scheduler Responsible for process access control to the CPU. Memory management Responsible for memory sharing among Different process. Virtual file system Abstracts the details of variety of hardware devices by presenting a common file interface to all devices. Network interface Provides access to several networking standard and variety of network hardware. Inter-process communications Provides process-to-process communications facility.

System Utilities Virtually every system utility that you would expect to find on standard implementations of UNIX has been ported to Linux. This includes commands such as ls, cp, grep, awk, sed, bc, wc, more, and so on. These system utilities are designed to be powerful tools that do a single task extremely well (e.g. grep finds text. inside files while wc counts the number of words, lines and bytes inside a file).

Other tools in Linux Tools and utilities Software that simplifies and automates the process of generating a Linux configuration that is tuned to specific embedded system’s requirement Assists the developer in debugging and tuning the system configuration, provides remote system maintenance and support GUI Modules, add-ons, drivers, and utilities to support the graphical display needs of embedded applications, including GUI toolkits, window manager, and browsers

APPLICATIONS LINUX Box LB1 - Embedded-PC LINUX Box LB1 is a highly efficient industrial computer / PC which is immediately ready to run without time-consuming software installations.

APPLICATIONS CONTD.. Very Effective in Server Applications such as DBMS / Databases Linux Is Widely Used In Embedded Systems Many Companies Are Launching Laptops With Pre Installed Linux

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