important features of Linux

* Full multitasking and 32-bit support. Linux, like all other versions of UNIX, is a real multitasking system, allowing multiple users to run many programs on the same system at

once. Linux is also a full 32-bit operating system, utilizing the special protected-mode features of Intel 80386 and later processors and their work-alikes.

* The X Window System. The X Window System is the de facto industry-standard graphics system for UNIX machines. A complete version of the X Window System, known as XFree86,

is available for Linux. The X Window System is a very powerful graphics interface, supporting many applications.

* TCP/IP (Transmission Control Protocol/Internet Protocol) support. This is the set of protocols that links millions of university and business computers into a worldwide network

known as the Internet. With an Ethernet connection, you can have access to the Internet or to a local area network from your Linux system. Using SLIP (Serial Line Internet Protocol) or PPP (Point to Point Protocol), you can access the Internet over phone lines with a modem.

* Virtual memory and shared libraries. Linux can use a portion of your hard drive as virtual memory, expanding your total amount of available RAM. Linux also implements shared

libraries, allowing programs that use standard subroutines to find the code for these subroutines in the libraries at runtime. This saves a large amount of space on your system; each application doesn't store its own copy of these common routines.

* The Linux kernel uses no code from AT&T or any other proprietary source. Much of the software available for Linux is free. In fact, a large number of utilities in Linux are developed by the GNU project at the Free Software Foundation in Cambridge, Massachusetts. However, Linux enthusiasts, hackers, programmers, and recently even commercial companies from all over the world have contributed to the growing pool of Linux software.

* Linux supports (almost) all of the features of commercial versions of UNIX. In fact, some of the features found in Linux may not be available on other proprietary UNIX systems.

* GNU software support. Linux supports a wide range of free software written by the GNU Project, including utilities such as the GNU C and C++ compiler, gawk, groff, and so on. Many of the essential system utilities used by Linux are GNU software.

* Linux is compatible with the IEEE POSIX.1 standard. Linux has been developed with software portability in mind, thus supporting many important features of other UNIX standards.

* Virtual memory support. Linux utilizes all of your system's memory, without memory limits or segmentation through the use of a virtual memory manager.

* Built-in support for networking, multitasking, and other features. You'll see this touted as "New Technology" in systems such as Windows NT. In fact, UNIX (and now, Linux)

has implemented this "new technology" for more than 15 years.

* Linux is cheaper to get than most commercially available UNIX systems and UNIX clones. If you have the patience and access to the Internet, the only price you pay for Linux is

your time. Linux is freely available on the Internet. For a nominal fee of anywhere from US $30 to US $90, you can save yourself some time and get CD-ROM or floppy-disk distributions from several commercial vendors (or from this book).