1.booting-booting (also known as booting up) is a bootstrapping process that starts operating system when the user turns on a computer system. A boot sequence is the initial set of operations that the computer performs when power is switched on.

2.GUI-A graphical user interface (GUI) is a human-computer interface (i.e., a way for humans to interact with computers) that uses windows, icons and menus and which can be manipulated by a mouse (and often to a limited extent by a keyboard as well).

3.linux-Linux can be installed on a wide variety of computer hardware, ranging from mobile phones, tablet computers, routers and video game consoles, to desktop computers, mainframes and supercomputers. Linux is a leading server operating system, and runs the 10 fastest supercomputers in the world.

^{4.Macintosh OS-}The Macintosh user experience is credited with popularizing the graphical user interface. The original form of what Apple would later name the "Mac OS" was the integral and unnamed system software first introduced in 1984 with the original Macintosh, usually referred to simply as the System software.

5.MS-DOS-MS-DOS grew from a 1981 request by IBM for an operating system for its IBM PC range of personal computers. Microsoft quickly bought the rights to (Quick and Dirty Operating System), also known as 86-DOS, from Seattle Computer Products, and began work on modifying it to meet IBM's specification.

6.MULTITASKING-In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for that task.

7.NOS-National Occupational Standards (NOS) specify UK standards of performance that people are expected to achieve in their work, and the knowledge and skills they need to perform effectively.NOS can be used to support any and all human resource management and development activities, as shown in the developed for Skills for Justice to support the use of the NOS for Legal Advice.

8.OS-An operating system (OS) is software, consisting of programs and data, that runs on computers, manages computer hardware resources, and provides common services for execution of various application software. The operating system is the most important type of system software in a computer system. Without an operating system, a user cannot run an application program on their computer, unless the application program is self booting.

9.system software-System software is computer software designed to operate the computer hardware and to provide a platform for running application software.System software is computer software designed to operate the computer hardware and to provide a platform for running programs such as "Windows Update" for Windows or "Software Update".

10.application software-Application software is contrasted with system software and middleware, which manage and integrate a computer's capabilities, but typically do not directly apply them in the performance of tasks that benefit the user. The system software serves the application, which in turn serves the user.

11.UNIX-a UNIX system is and its associated trademark in trust for the industry. 

12.Utility programs-A program that supports using the computer, an application or a development environment. Also called "utilities," utility software is programmed like any other software, except that it plays a supporting role. Usually relatively small programs, they typically perform a limited number of tasks.Utility programs include file management (creating, moving and renaming folders, copying and deleting files), file search, comparing file contents as well as performing diagnostic routines to check the performance and current health of the hardware.

13.Windows-Windows Update is included in Control Panel. In the future, to check for updates (or if this webpage doesn’t open Windows Update automatically):
  Click the Start button, click All Programs, and then click Windows Update.

Microsoft Windows is a series of operating systems produced by Microsoft.

Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical use

14.Windows CE-Windows CE (officially known as Windows Embedded Compact), is an edition of Windows that runs on minimalistic computers, like satellite navigation systems and some mobile phones. Windows Embedded Compact is based on its own dedicated kernel, dubbed Windows CE kernel. Microsoft licenses Windows CE to OEMs and device makers.

15.Windows mobile- is a mobile operating system developed by Microsoft that was used in smartphones and mobile devices, but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone 7, which does not run Windows Mobile software.

*Differentiate

Mac OS vs Windows vs UNIX- Unix vs. Microsoft Windows

Microsoft Windows is widely regarded as the epitome of insecure platforms a platform fraught with innumerable security problems. Windows systems top the charts in perhaps every major vulnerability and incident list. In contrast, Unix systems are perceived to be considerably more secure.  
How Did Windows Become "So Insecure"?

I posed this question to a few people: technology experts, and non-technical users. I found that very few people had actually ever given this any serious thought. They "just knew" that Windows is "the most insecure platform." Those who were willing to think on-the-fly ascribed their beliefs to gut-feeling, perpetual digital disasters crashing down upon Windows (as experienced first-hand or as reported by the media), statistics (incidents and vulnerabilities published by respectable organizations), folklore, inherent (sometimes inexplicable) hatred of all things Microsoft, inherent affinity for Unix, etc. Some conjectures took Microsoft's monopoly into account, concluding that Microsoft "doesn't really care" about security, as they can afford not to, and still be successful.