Personal Computer Information

Mac OS X is a line of graphical operating systems developed, marketed, and sold by Apple Inc.. Mac OS X is the successor to the original Mac OS, which had been Apple's primary operating system since 1984. Unlike its predecessors, Mac OS X is a Unix-based graphical operating system. The most recent version of Mac OS X is Mac OS X 10.6 "Snow Leopard", and the current server version is Mac OS X Server 10.6. On October 20, 2010, at a keynote event held at Apple's headquarters in Cupertino, CA, Apple announced Mac OS X 10.7 "Lion", which is slated for arrival in the summer of 2011.

Linux is a family of Unix-like computer operating systems. Linux is one of the most prominent examples of free software and open source development: typically all underlying source code can be freely modified, used, and redistributed by anyone.^[36] The name "Linux" comes from the Linux kernel, started in 1991 by Linus Torvalds. The system's utilities and libraries usually come from the GNU operating system, announced in 1983 by Richard Stallman. The GNU contribution is the basis for the alternative name GNU/Linux.^[37]
Known for its use in servers as part of the LAMP application stack, Linux is supported by corporations such as Dell, Hewlett-Packard, IBM, Novell, Oracle Corporation, Red Hat, Canonical Ltd. and Sun Microsystems. It is used as an operating system for a wide variety of computer hardware, including desktop computers, netbooks, supercomputers,^[38] video game systems, such as the PlayStation 3, several arcade games, and embedded devices such as mobile phones, portable media players, routers, and stage lighting systems.

A computer user will apply application software to carry out a specific task. System software supports applications and provides common services such as memory management, network connectivity, or device drivers; all of which may be used by applications but which are not directly of interest to the end user. A simple, if imperfect analogy in the world of hardware would be the relationship of an electric light bulb (an application) to an electric power generation plant (a system). The power plant merely generates electricity, not itself of any real use until harnessed to an application like the electric light that performs a service that benefits the user.
Typical examples of software applications are word processors, spreadsheets, and media players. Multiple applications bundled together as a package are sometimes referred to as an application suite. Microsoft Office and OpenOffice.org, which bundle together a word processor, a spreadsheet, and several other discrete applications, are typical examples. The separate applications in a suite usually have a user interface that has some commonality making it easier for the user to learn and use each application. And often they may have some capability to interact with each other in ways beneficial to the user. For example, a spreadsheet might be able to be embedded in a word processor document even though it had been created in the separate spreadsheet application.
End-user development tailors systems to meet the user's specific needs. User-written software include spreadsheet templates, word processor macros, scientific simulations, graphics and animation scripts. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is.