Operating System (OS)

Operating System (OS) is the software component of a computer system that is responsible or the management and coordination of activities and the sharing of the resources of the computer. The operating system acts as a host for application programs that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware. This relieves application programs from hawing to manage these details and makes it easier to write applications. Almost all computers, includding game consoles, use an operating system of some type. Some of the oldest models may however use and embedded OS, that may be contained on a compact disk or other storage device.

Operating system offer a number of services to application programs and users. Apllication access these service through application programming interfaces or system calls. by invoking these interfaces, the application can request a services rom the operating system, pass parameters, and receive the result of the operating system. User may olso interract with the operating system by typing commands or usinga graphical user interface (GUI). For hand-held and desktop computers, the GUI is generally considered part of the operating system. For large multi-users system, the GUI is generally implemented as an application program that runs outside the operating system.

Common contemporary operating system include Microsoft Windows, Mac OS, Linux and Solaris. Microsoft windows has asignificant majority of market share in the desktop and notebook computer markets, while servers generally run on linux or other unik-like systems. Embedded device markets are split amongst several operating system.

• Microscoft Windows

Microsoft Windows presently supports NTFS and FAT file system, along with network file system shared from other computers, and the ISO 9660 and UDF file system used for CDs, DVDs and other optical discs such BluRay. Under windows each file sistem is usually limited in application to certain media, or example cds must use ISO 9660 or UDF, and as of windows vista, NTFS is the only file system, comparing closely in performance to Linux.

• Mac OS X

Mac OS X support HFS+ with journaling as its primary file system. It is derivered from the Hierarchical File System of the earlier Mac OS. Mac OS X has facillities to read and write FAT, NTFS, UDF, and other file systems, but cannot be installed to them. Due to its UNIX heritage MAC OS X now supports virtually all the system supported by UNIX VFS. Recently Apple Inc. Started work on porting Sun Microsystem's ZS filesystem to Mac OS X and preliminary support is already available in Mac OS X 10.5.

• Linux and UNIX

Many Linux distributions supports some or all of ext2, ext3 ReiserFS, Reiser4, JFS, XFS, GFS2, OCFS, OCFS2 and NILFS. The ext file system, namely ext2 and ext3 are based on the original Linux file system. Others have been developed by companies to meet their specific needs, hobbyists, or adapted from UNIX, Microsoft Windows, and other operating systems. Linux has full support for XFS and JFS, along with FAT (the MS-DOS file system), and HFS which is the primary ile system for macintosh.
In recent years support or Microsoft Windows NT's NTFS file system has appeared in Linux, and is now comparable to the support available for other native UNIX file system. ISO 9660 and UDF are supported which are standart file systems used on CDs, DVDs and BlueRay discs. It is possible to install linux on the majority of the majority o these file systems. Unlike other operating systems, Linux and Unix allow any file system to be used regardless of media it is stored on, whether is a hard drive, CD or DVD or even a contained within a file located on an another file system.