SSP2122 COMPUTATIONAL PHYSICS

What is Linux?

Linux is a computer program that manages how computation and communication is done in the computer system. Physically it is a small program, about 1 Mbytes in compressed form in the hard disk, actually known as the kernel. By itself a kernel is not an operating system and useless to ordinary computer users . It has to be supported by many other programs that makes up a system, hence becomes a computer operating system or simply called OS.

Linux OS (the kernel plus the other supporting programs) is a free Unix-type operating system originally created by Linus Torvalds in 1991 with the assistance of developers around the world. It's developement was and still done under the GNU General Public License, and the source code for Linux is freely available to everyone.


Working environment

In its simplest form, one can use the computer under linux via a command line interface (CLI) known as the linux console. In this mode however, we only have a very limited graphical capability.

In this age of computer technology, users prefer to work with the computer in an environment that has a graphical interface and for that there exist a special program called X Windows system, or simply known as "X", to allow people to work using windows interface in linux (or other OS like it). But by itself, X Windows is a very primitive graphical system and not friendly as graphic user interface. Hence a number of programs were build on top of the X Windows that provides more friendly graphical working environment known as window manager. Some of them has grown to be a comprehensive system and they are now called graphical desktop environment (GDE). Examples of popular desktop environment for linux are GNOME and KDE. Most of the computers in our lab were installed with both of these GDEs. You can try any of them by choosing the session type in the login manager before logging into the system. Which of these is the better is a matter of personal preference and taste. Although GNOME and KDE can be considered as very good GDEs they however are very big in RAM consumption and on a computer that has less than 256 Mbytes RAM, system performance degrade significantly. If your computer's RAM is small (less than 128 Mbytes), you can choose to use just the window manager without desktop environment and gain some speed performance. Examples of lean window managers are FluxBox, Fvwm, Mwm, etc. Visit http://xwinman.org/ for a comprehensive guide and introduction to the many window managers for the X Windows system.