$92,000 Net revenue - $52,000 Variable expenses = $40,000 Contribution margin. This ratio is only used from the perspective of deriving the lowest possible acceptable price for a unit. In reality, a variety of other pricing concepts can be used to establish higher price points for products.
Steam OS is possibly the best, most known and used cross platform Linux gaming distribution based on  Debian Linux, it is an assortment of numerous entertainment software, you can think of it as a complete gaming platform for Linux.
Windows is the most popular among them because it is one of the best os and it is already used in lots of computers. And, large amount of softwares are made for windows. Jean-Clod. Well, for Desktops/Servers, there are 4 main types of operating systems: Windows, and the three UNIX-based ones: Linux, MacOS, BSD. most OS' are based on those. I know, there are ones that aren't forks of those, but these aren't really used anymore. But I am no expert.