Design Principles

Linux is a multi-user, multitasking system with a full set of UNIX-compatible tools..

Its file system adheres to traditional UNIX semantics, and it fully implements the standard UNIX networking model.

Main design goals are speed, efficiency, and standardization.

Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification.

The Linux programming interface adheres to the SVR4 UNIX semantics, rather than to BSD behavior.

Components of a Linux System

Like most UNIX implementations, Linux is composed of three main bodies of code; the most important distinction between the kernel and all other components.

The kernel is responsible for maintaining the important abstractions of the operating system.

  1. Kernel code executes in kernel mode with full access to all the physical resources of the

      computer.

  2. All kernel code and data structures are kept in the same single address space.

The system libraries define a standard set of functions through which applications interact with the kernel, and which implement much of the operating-system functionality that does not need the full privileges of kernel code.

The system utilities perform individual specialized management tasks.