We demystify the Linux Kernel by bringing forth some features that are common to all versions of Linux OS.
Wednesday, September 25, 2013: Linux Kernel is a piece of code that is common to all versions of Linux. Proper understanding of the Linux kernel allows you to modify the operating system (OS) so as to incorporate support for the features you want. Every Linux kernel comes with these features:
Multiuser – You can not only have multiple user accounts on a Linux system, but can also have multiple users logged in and working on the system simultaneously. Also, the users can arrange their own environments the way they want. It is possible to have user accounts password-protected, so that users can monitor who gets access to their applications and data.
Multitasking - In Linux, it is possible to have several programs running together, which means that you can not only have multiple programs running together, but that the Linux OS can itself have programs running in the background. Majority of these system processes make it feasible for Linux to work as a server with numerous background processes responding to the network for requests to log in to your system, display an Internet page, print a document, or copy a file.
Graphical user interface (X Window System) - The robust framework for working with graphical applications in Linux is dubbed as the X Window System (or simply X). X manages the functions of opening X-based graphical user interface (GUI) applications and showing them on an X server process (the process that controls your screen, mouse, and keyboard).
Hardware support – It is possible to organize support for roughly every type of hardware which can be connected to a pc. You can get support for floppy disk drives, CD-ROMs, removable disks, sound cards, video cards, tape devices, and lots of other things you can think of.
Networking connectivity – Linux provides support for a range of local area network cards to connect your Linux system to a network, modems, and serial devices. Additionally, LAN protocols, including Ethernet -both wired and wireless, all the most admired upper-level networking protocols can be integrated. TCP/IP is the most popular of these protocols is which is used for connecting to the Internet while other protocols, such as IPX and X.25 are also available.
Network servers – Linux provides best networking services to the client computers on the LAN and also to the entire Internet. It offers you a range of software packages to enable you to use Linux as a print server, file server, FTP server, mail server, Web server, news server, or workgroup (DHCP or NIS) server.
Application support – Due to the compatibility with POSIX and various other application programming interfaces (APIs), a large variety of freeware and shareware software is available for Linux. Majority of GNU software from the Free Software Foundation will run in Linux.
Fonte: Everything You Wanted To Know About The Linux Kernel