Chapter 5 Logging to a Linux system!

Linux is a Multi-user and Multi-tasking operating system. The system can be used by more than one user simultaneously, and the computer can also run multiple programsat a time.

Types of Multi-tasking :-

1. Cooperative multitasking – Decision is taken by application/programs cooperatively. A poorly designed program or a crashed process can potentially crash the entire operating system since it could prevent a process from relinquishing the CPU to other processes.

2. Preemptive multitasking – Decision is taken by OS. Permits the system to respond immediately to important external events, such as incoming data from a keyboard or network.

Types of Logins :-

• Command Line login
• GUI based login

Case-Sensitivity in login : fossil and FOSSIL are two different user names! The same applies to the passwords!

Virtual Consoles -

The linux based system provides different virual consoles for login.
Alt+F1 ,Alt+F2 till Alt+F6 (by default) sometimes it is Ctrl+Alt+F1 allows you to multi-task in console mode also. Alt + F7 is the GUI

How to login:-

• Console – ttys and pts    (ttys is Terminal Type and  pts is  pseudo terminal).

• Serial Terminal – Hyperterminal

• Network Connection – SSH / telnet etc( connects between the systems remotely )

CUI  :- CUI (Composite User Interface) is a compound type of user interface which incorporates the features of the GUI (Graphical User Interface) and the CLI (Command Line Interface) by realizing both interface in one area at the same time

GUIs In Linux :-

Unlike Windows, GUI is an application in itself.

XFree86, Xorg  are two free X server implementations and VNC – client/server architecture The Client and Server communicates using TCP/IP protocol even in local system and not the usual way of local communication, Unix sockets.

In Linux we have a  dozens of choices for  GUI:-

Desktops:-

• GNOME
• KDE
• XFCE
• CDE

Window Managers – Clients application of X :-

• FVWM
• IceWM
• FluxBOX
• Enlightenment
• BlackBox
• Metacity – GNOME’s WM

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