Features "UNIX/Linux"

Features
UNIX flavors incorporate a kernel, which constitutes the core of the operating system. The kernel can access hardware and communicate with various types of user interfaces. The two most popular user interfaces are the command-line interface (called a shell) and the graphical interface (X Window System). The UNIX kernel is similar to the core operating system components of Windows Server and NetWare. In UNIX, the kernel is typically simple and, therefore, powerful. Additionally, the kernel can be recompiled to include support for more devices. As a matter of fact,
some flavors (like Linux) include the source code so that you can create your own flavor of UNIX. 
      The UNIX flavor that has been receiving the most attention lately is Linux. Linux is a fairly easy-to-use (as UNIX goes, anyway) flavor developed by Linus Torvalds at the University of
Helsinki, Finland. He started his work in 1991 and released version 1 of the Linux kernel in 1994. As this book is being written, the current Linux kernel is version 2.2. Since Linux development
teams add features daily, it’s only a matter of time before a new release.
      Linux runs mainly on the Intel platform, although some distributions run on Rapid Instruction Set Computing (RISC) processors such as the MIPS and Alpha. Attempts have been made,
successfully, to run the RISC version on other platforms, such as the Macintosh. Linux is easy to install, and most distributions are free and include the source code. Hardware requirements
can vary widely with each distribution.
     And there are various flavors of Linux. People acquire Linux, come up with a new feature, recompile Linux with the new feature, and then redistribute it. According to Linux’s distribution
agreement (called the GNU public license), any sale or distribution must include the source code so that others can also develop custom Linux applications.
      Most Linux distributions include a full suite of applications, such as a word processor, the X Window System graphical interface, and source code compilers. Additionally, most UNIX applications that comply with the POSIX standard should run on Linux with little or no modification.

Because Linux is a flavor of UNIX, it comes with network support for TCP/IP. In particular, Caldera’s OpenLinux is making its mark in the networking world. OpenLinux was developed for corporate
networking, so it supports multiple protocols (including Point-to-Point Protocol [PPP], Apple- Talk, IPX, and SMB). It also includes support for integration with other network operating systems.
    Two other distributions of Linux should be noted: Red Hat and Slackware. Red Hat Linux is the most portable version of Linux, with code that runs natively on the Intel, Alpha, and SPARC
processors. The Slackware distribution was specifically designed for the Intel platform and, as such, supports many PC hardware devices, including Ethernet and multiple (up to 16) processors.

NOTE:

For more detailed information on Linux, as well as locations to download it, check out www.linux.org. For a list of the various English Linux distributions,check out www.linux.org/dist/english.html.