Operating System Variants

There are a lot of options when it comes to operating systems out there, but why are there so many different operating systems? Why is there the variety that we have, and why do some of them look very similar and feel very similar while others are very different?

Market Share

First, some context. When it comes to desktops and laptops, usually there's some sort of variant of Windows that are sold on those. 72% of the market are Windows machines, 15% is macOS, so really most of the market is between Windows and Apple, or Microsoft and Apple. We do see some variants though. Linux takes up 4%, and if you include Chrome OS in that, because that's just a variant of Linux, then what we have is about 6%. And then there are 6% unknown that are out there as well.

Now that was just for desktops and laptops. It looks a little different when we're talking about all devices that are shipped with operating systems on it. When we take a look at this, and this is a little bit older stats here but it's going to give us an idea of what's out there, Windows only takes up about 12% of the market here. So we're seeing quite a bit less here, and that's because they don't have a strong presence on phones and on tablets and some of the other devices. What we see heavily is that it is a market that's based largely on Android and Linux, which is 54% of the market. We also see iOS and macOS, which is about 12% of the market, and other devices, which is around 22% of the market.

One thing to understand about this though is that there are a lot of different versions of Windows. There's also a lot of different versions of iOS and macOS. There's also a lot of different versions of Android and Linux, a lot of versions of Linux, and so there's a lot of other variants that are involved here as well.

The Unix Family Tree

I looked up this family tree of some of the Unix-like systems, and this is just a small variety of the different operating systems that are out there. This includes Linux, BSDs and Solaris, and the more popular distros. What we call it when somebody creates a branch off of this is a distro, and it's a distribution, a distribution of Linux.

Here we see the Slackware distro with a bunch of branches off of it. If I scroll down we can see Red Hat here with the branches off of it. We've also seen Fedora, which is the branches off of it. Those are some big Linux versions that are out there. Ubuntu, or Debian, is a big one, so we see the Debian branch right here, and then off of the Debian branch we can scroll up here, somebody's created Ubuntu, and then from Ubuntu one of the ones that branched off of it is Mint. So those are all popular branches from all of this, and you can see the list just keeps going on and on. There's a lot of different distros out there that you could choose from.

The Abstraction Layers

Before we start looking at all these variants, let's first revisit this abstraction layer we call the operating system. As an abstraction layer, it's communicating with the hardware, but within here then it's presenting itself, it's creating some sort of representation to the apps and to the users that are interacting with it. So it's this layer, this abstraction layer, of representing on one side and then giving commands to that hardware on the other side.

Now within your operating system you actually have multiple abstraction layers. One of the abstraction layers in here is the kernel. The kernel interacts directly with the hardware and it separates it out from the user side of this. So there's a user side that interacts with the apps and interacts with the users, and then there's the kernel side that interacts directly with the hardware.

What essentially is happening here is there's multiple layers of these abstractions. We're entering commands into the user mode, the applications are entering commands into the user mode, which then get translated into something that the kernel mode can accept and then process. And then what happens is that gets translated into machine language, which gets submitted into the hardware.

Why So Many Variants

So why are there so many variants out there? Let's give an example. Let's say TechKnowSurge is actually manufacturing some sort of desktop, some sort of hardware, and what we want to do is we want a custom experience for the end user that interacts with our hardware. What we're going to do is first go and borrow somebody else's kernel, because we don't want to create that, and we may make some changes to the front end of the operating system and then create our own apps, all to give a unique feeling to our end users so that they are experiencing things. We're going to call this whole operating system right here TKS, so this is the TKS OS.

But we also start creating phones and tablets, and we want it to also have a similar look and feel but slightly different. So what we're going to do is take that same kernel with maybe parts of the same user mode and some of the same apps, but not all the same apps. We're going to recreate some of them, and so we're going to create now a secondary OS, and maybe we call this TKS Mobile, so we're going to call this TKS Mobile OS. Now we suddenly have a different variant of this, so then we are going to push it out on our phones, and people are going to get that experience on their phones.

Android could be an example of this. What they've done is they borrowed the Linux kernel and added their own user mode side of this and their own apps as part of this to create a unique experience on Android phones, but it really is just a Linux system.

A History of Operating Systems

Now let's take a look at the history of operating systems. One thing to understand about this is that this is a very simplistic view of it, so I'm just going to categorize things like Windows as being Microsoft right here. I'm going to categorize all of the operating systems that Apple has into one category, and Linux as well. But realize there's a lot of variants within here, and even Microsoft has redeveloped their operating system multiple times, and same thing with Apple, there are many different times that they've redeveloped their system. So this is a very simplistic view of this, but this will drive home the point of how come we have so much variance involved with the different operating system options we have.

As we developed microprocessors, we also developed the need to have an operating system, something that would control that hardware. So we saw a lot of different various operating systems come out in the 1960s. Towards the end of the 1960s, Bell Laboratories started developing Unix, and that was starting to market here in the early 70s. So we've got Unix that came out.

Now the thing with Unix is you had to license it from Bell Laboratories. That's how they made their money off of it. So if you wanted to use the Unix code you'd have to give them money to license it, and that's where something like BSD came into effect. BSD is the Berkeley Software Distribution. Berkeley took the Unix code, paid the licensing fee, to create BSD, and that was their version of an operating system that they used.

One of the problems with this is that licensing Unix could be very costly to do. So what you had is a lot of copycats that tried to mimic that same environment. A lot of operating systems were created with a Unix-like system, so it didn't have the base code as being Unix, but it did operate and had a similar feel to it as Unix did, so we call it Unix-like. One example of this that came out actually a little bit later is FreeBSD. FreeBSD is a Unix-like system. What happened is Berkeley wanted a free version of their BSD, so they took out the Unix code and recreated it so that they could give it away for free.

Microsoft was a software company that wanted to develop and sell applications, but in order for them to really distribute a lot of their applications they wanted some control over the operating system. So they developed their own operating systems and started selling them in the early 80s, and so Microsoft became a player in this operating system arena, and later on discovered how much of a money maker it could be and really dominated the market, and still does to this day, at least from a desktop and laptop standpoint.

Another spin-off from Unix is Apple. What Apple did is they started developing their own branch, where they created their operating system for their devices, in the 90s.

In the 90s there was a software engineer named Linus Torvalds, and he didn't want to pay the high cost of licensing Unix, and there were not a lot of free options. FreeBSD had not come out at this point, and so he wanted to develop an operating system that was free that he could use and others could use. So he started working on Linux, and that came out in the early 90s, and FreeBSD just came out a little bit later. In fact, if FreeBSD was out before he developed this, we probably wouldn't have Linux today. So that's where Linux came about, as a free version that Linus created so that we could utilize it and not pay these high license fees.

Compatibility and the Three Options Today

This does create some compatibility issues, and that's because your kernel is quite a bit different and any of your user mode is quite a bit different. So if you create an app, a lot of those apps can be compiled differently to operate on the different operating systems, but you do have to have different versions of whatever that app is so that it can run on a Linux system or an Apple system or a Windows system. So those are three different versions that you have to release for any app that you want to release, if you want to have them run on all three of those platforms.

Nowadays you have three amazing options. You've got Microsoft, Apple and Linux, that are great operating systems, and there's really not a reason to use a lot of these other Unix-like systems, although there's a few that are still around being used. Same thing with Unix, there's not a strong reason to do that. And so you see the popularity of Unix and these other Unix-like systems, because Linux is a Unix-like system, you see that most of those have faded. So really the three prevalent ones we have now are the operating systems that come from Microsoft, from Apple, or from Linux.

Although one reason why somebody may want to go back and pay the licensing fees for a Unix or Unix-like system is because if they did develop it in Linux they may have to give their product away for free, because Linux is free, and whatever you develop within Linux, if you're giving that away as part of the code, then all of the code needs to be given away for free as well. So there are some licensing issues there.