OK, think of an OS like a car: it is comprised of several parts, but the heart of it is the engine. Without it, the car is simply a chunk of metal and plastic on wheels. Well, for operating systems that heart is the kernel. it is the program that takes control of the hardware in a computer, and allows other programs to take turns using it. Back in the late 60's, AT&T was a really big company, so they had their own research and development laboratory: Bell Labs. In there, programmers Ken Thompson and Dennis Ritchie developed an operating system: UNIX. This was a time where computers were the size of a couple fridges, and instead of a keyboard and screen, you used a special electric typweritter called a teletype to "chat" with a computer (that is the grandpa of terminals, BTW). Here is a video of one of those machines running UNIX V0: https://www.youtube.com/watch?v=pvaPaWyiuLA because of it's advantages, and because when you bought it you got it's soruce code so you could adapt it to the computers you had, UNIX became quite widespread, even to the extent of other companies developing their own versions, like HP's HP-UX, Sun's Solaris, and even Microsoft did one called Xenix. Here is a video from 1982 where they say the advantages of UNIX: https://youtu.be/tc4ROCJYbm0 In that video, they show that an UNIX OS is comprised of three "layers": The kernel, which as I said, is the heart of the OS The shell, which is the terminal program you use to interact with the OS The utilities, which are all those programs you call from the terminal to do your work. Keep in mind that info. Long story short, AT&T wanted to control UNIX to make a profit, so they started to sue some UNIX clone developers on the basis of copyright infringement. They even sued the the University of Berkeley in California, as they were doing one of the most popular UNIX variants: the Berkeley Software Distribution (BSD). That ruffled some feathers along the people who used UNIX, including Richard Stallman, which was a wacky dude working on the AI lab at the Massachusetts Institute of Technology. He was so pissed at AT&T for suddenly changing gears from an "open" model to a restrictive one that was there only to suck money from people. Because of that (and problems with a printer), he started the Free Software movement (ya know, free as in freedom, not like free beer) and to kickstart it, he did three things: Write the General Public License (GPL), which is a "terms and conditions" document that you can apply to a program to make it free software Start the Free Software Foundation to promote, defend, and spread the Free Software Movement Start developing a fully free operating system that was compatible with UNIX, but developed from the ground up so AT&T could not sue them. Well, that OS that Richard Stallman started is GNU. Fun Fact: there is a running joke that GNU are initials, and they stand for "GNU is Not Unix" Stallman and others slowly bus steadily started to develop tons of programs to make the GNU OS a reality: the GRUB bootloader, the GCC code compiler, the BASH shell program for the terminal, etc. But one key component was missing: the Kernel. Some candidates were considered for it, with the biggest contender being the Hurd kernel, which is yet another project under the GNU OS umbrella. But that thing, much like Half Life 3, never came to be. In the meantime, a random student from the University of Helsinki in Finland made just for fun a UNIX-like kernel. Well, turns out that he developed "by accident" the kernel that the GNU OS lacked, finally completing the project. That student was Linus Torvalds, and that kernel was Linux. That is why the Copy-pasta is about. Linux is only the name of a kernel, but many of the other components that make the base of many distros out there come from the GNU OS project. Now, comparing it to Windows is a bit hard as there not that much direct equivalent. Windows also has a kernel, which is the NT kernel, but the rest of the OS is just Windows. The difference comes because back in the 80's, Microsoft Disk Operating System (MS-DOS) was the OS that home computers used, which worked only in the terminal. Windows started as an MS-DOS program that put a graphical user interface on top of MS-DOS, and that model continued up to Windows Millennium Edition. Meanwhile in the 90's Microsoft started to experiment with a proper OS kernel: the New Technology kernel (NT), but it was so heavy that only workstations could run it, so NT was only used on the "Professional" version of Windows. That changed with Windows XP in 2001, as home computers were powerful enough that they could run NT with no trouble, so in that version of Windows they ditched the MS-DOS background and went full NT, up to this day with Windows 11. macOS on the other hand is more similar, as that one is a UNIX-like OS, making it a sort of "cousin" of Linux. Remember that I said that the Berkeley university did their own UNIX variant called BSD?, well, once they got rid of the AT&T demand, they released it's OS under an open bespoke license (the so famous BSD 3-clause license). Unlike the GPL (which Linux and all of GNU uses), where all derived code needs to also be publicly released under the GPL license or similar, the BSD license does not have such clause, so you can take BSD, make some changes, and make it private. BSD is the bases of lots of OSes out there, like the ones on the PlayStation 4 and 5, the Nintendo Switch, lots of home routers, and macOS. Maybe you have heard that in the 80's Steve Jobs was kicked out of Apple, so then he went to make his own company: NeXT. Well, those NeXT computers used an OS that was based on BSD: NeXTSTEP. It used lots of things from BSD, but instead of using the BSD kernel, they instead opted for Mach, which was a kernel that some guys at the Carnegie Mellon University were developing for research (Jobs even hired some of those people to work on NeXTSTEP). Meanwhile Apple without Steve Jobs was a dumpster fire, including macOS (which at the time was a bespoke OS developed in Apple). That prompted Apple to ask Steve to return, so he did. In the process Apple bought NeXT, and took it's OS NeXTSTEP as the basis for macOS X (the one that featured on those colored macs from the early 2000s). Being technical, NeXTSTEP evolved into an open source (but not free) OS called Darwin, and it's kernel (based upon the Mach kernel) called XNU. Apple then takes that "XNU/Darwin" thing and makes macOS out of it (and also tvOS, iOS, watchOS, visionOS and whateverOS they come up nowdays). Hope I was clear enough, but if not, feel free to ask questions. More on reddit.com

Solution For What is the full form of GNU? (a) Great New Unix (c) GNU is New Unix (b) Good New Unix (d) GNU is Not Unix Who developed the Linux kerne More on askfilo.com

In any Linux distribution the GNU tools form the traditional Unix command line interface for users, almost all the system administration commands are Linux own, and (except for the Gnome environment, which associated itself with GNU) the graphical environments are not GNU. More on opensource.stackexchange.com

GNU is an operating system that implements POSIX (mostly). GNU can be built with different kernels. HURD is one, but there was also Debian GNU/kFreeBSD for some time. You can also run GNU on Windows with WSL (though WSL 2 runs GNU on Linux in a VM). Similarly, Linux can be used with different user-land software. Many Linux operating systems are not POSIX. For example, Android is a popular Linux operating system. There are also POSIX operating systems that use Linux and a user-lands other than GNU, such as Alpine. Because this two things can be used together, but can also be used with different components, it's useful to refer to that combination specifically in many contexts. Fedora, Debian, arch, and gentoo are all GNU/Linux operating systems. Alpine, Android, and dd-wrt are all Linux operating systems. Generally, when I'm talking about a feature of the kernel, I'll refer to Linux systems, because the feature will probably be present in all of them. But of I'm talking about Unix-like systems, I'll usually refer to GNU/Linux to differentiate it from other Linux systems. More on reddit.com