Your question makes no sense. Either that means you need to learn English. Or if you can already understand English, please stay away from computers. For everyones' sake.
explain the different components of operating system in details
An easy way to find out what operating system is installed onto your notebook would be to open your system's control panel. From there you need to go to the "System and Security" section, and from there click on the "System" link. The page will show you your current operating system, as well as all the other details about your notebook.
Windows 8 is the most current windows client operating system.
If the PC is made by Apple then the current Apple operating system is 100% compatible. Other PCs with other operating systems will have varying degrees of compatibility with the current Apple operating system.
linux
compitibility
there is no "linux operating system". linux is merely a kernel that operating systems can be built upon, of which there are dozens if not hundreds
virtual real mode
Yes, a computer operating system can be downloaded onto your computer. One of the most common file formats to download operating systems is the .img file format. The .img file format can be used by programs like Oracle's VirtualBox, to create a virtual computer on your own computer. This uses the operating system that is saved in the .img file without overriding your current computers operating system and basically creates another "fake" or virtual computer within your own computer. However, these operating systems can also be used to replace your current operating system or to dual boot your computer, this means to have two operating systems installed on one computer at the same time. Operating systems can also be downloaded for the sole purpose of replacing your current operating system. For example, when a person upgrades their computer from running Windows 8.1 to Windows 10, they are essentially downloading a new operating system on to their computer from Microsoft, but in a way that it completely replaces their current operating system.
IOS8 stands for Internet Operating System. The number 8 recognizes the current number of the operating system, meaning that there were previously 7 other operating systems made before the 8th was released.
go to windows .com it has all the information
On a Mac click on the Apple menu icon (top left corner) and select About this Mac. An informative window with details of your current version of Mac OS X will appear.