Difference Between Windows, Linux, Unix and Mac??

In simple terms: MacOS is the basis for most graphical user interfaces (GUIs). It's designed to be so simple that a one-eyed chimp could use it (which is fairly appropriate given Apple's target market). Windows is Microsoft's GUI that is based on the same principles but is generally more annoying and less stable because PCs aren't buy-the-box machines. They can have almost any hardware in them, so the OS has to be more complicated and unstable. The advantage is that you can upgrade rather than throw out your old machine and buy a new one. Unix is a "serious" operating system. It's extremely powerful and runs on a command line rather than a GUI. There are, of course, GUIs that fit on top of it but the OS itself is underneath. It's awesomely powerful - for example, you can delete the entire disk contents (including the OS) with a single command. It's efficient, too, and still forms the basis for the majority of large business installations. Linux is, effectively, the free version of UNIX. It's built in a similar way but is an "open source" system built by fans and can be seen as the "next generation" UNIX, if you like. It's better in some ways (like for server farms/cloud computing) and worse in others. It gets confusing because Linux comes in a huge number of "flavours" (i.e. the basic code has been built on in different ways by different people). Think of it this way: you want to fly to Hong Kong. MacOS is like going to the airport, flashing your credit card and ID, paying tons of money, getting on a chartered plane and being treated like a VIP all the way. Windows is like going to the airport, paying a reasonable price, going through security, being delayed a bit at the airport and travelling in standard class where you get a cheap meal and a drink. You get there but it's a bit more stressful. Unix is like flying on your own plane. You have to do all the work yourself and it's uncomfortable but you get there ten times quicker. Linux is like being given a bunch of spare parts. You have to build the plane before you fly it yourself.

Mac OS is a certified derivatives or flavor of UNIX OS. All Linux OS derivatives or flavors are just feels like UNIX and not a certified by UNIX OS. Not all thousands of Linux operating systems different kind of derivatives or flavors are not truly free to use or instal. Mac OS are not free as well and a proprietary operating systems of every Apple Macs. Mac OS is a mixed or an integrations of other kind of Operating Systems such FreeBSD Linux and NEXTStep OS a UNIX also. Mostly Linux operating systems many different developers are open source communities. That's why mostly applications software are free to use. UNIX are primary developed by Bells AT&T Bell Labs. Windows by Microsoft are already an almost obsolete or left behind operating system. Though they are still the most enjoyed computer users either via genuinely or genuinely pirated copy of MS Windows OS.