What is Linux?

Linux is a freely distributed operating system that behaves like the Unix operating system. Linux was designed specifically for the PC platform and takes advantage of its design to give users comparable performance to high-end UNIX workstations. Many big-name companies have joined the Linux bandwagon such as IBM and Compaq, offering systems pre-installed with Linux. Also, many companies have started Linux packages, such as Red Hat, Corel, and Samba. However, they can only charge for services and documentation packaged with the Linux software. More and more businesses are using Linux as an efficient and more economical way to run their networks.

Linux is a complete multitasking, multi-user operating system that behaves like UNIX in terms of kernel behavior and peripheral support. Linux has all the features of UNIX and boasts of its open source code and mainly free utilities.

The Linux kernel was originally developed for the Intel 80386, which was developed with multitasking as one of its features. The kernel is the lowest-level core factor of the operating system. The kernel is the code that controls the interface between user programs and hardware devices, the scheduling of processes to achieve multitasking, and many other aspects of the system. The Linux kernel is a monolithic kernel; all the device drivers are part of the kernel proper. Despite the fact that most of Intel's CPUs are used with single-tasking MS-DOS, Linux makes good use of the advanced multitasking features built into the CPU's instruction set. Linux supports demand paging, which means that only the sections of a program that are necessary are read into RAM. Linux also offers support for copy-on-write, a process that if more than one copy of a particular application is loaded, all tasks can share the same memory. When large memory requirements are needed and only small amounts of physical RAM are available, Linux has another feature called swap space. Swap space allows pages of memory to be written to a reserved area of a disk and treated as an extension of physical memory. By moving pages between the swap space and RAM, Linux can, in effect, act as if it had much more physical RAM than it does, with the cost of some speed due to the hard drive's slower access. Linux also supports diverse file systems, as well as those compatible with DOS and OS/2. Linux's file system, ext2fs, is intended for best possible use of the disk.