Those changes didn't change the fundamental architectural basis of Windows. There are quite a few subsystems in the NT architecture, let's look at them in turn,

Those changes didn't change the fundamental architectural basis of Windows. There are quite a few subsystems in the NT architecture, let's look at them in turn, but first have a look at the following diagram which I created years ago and hasn't changed terribly: https://en.wikipedia.org/wiki/Architecture_of_Windows_NT#/media/File:Windows_2000_architecture.svg https://en.wikipedia.org/wiki/Architecture_of_Windows_NT#/me... * the HAL - there have been changes here, but nothing so fundamental that can't be built upon * kernel mode drivers - these have changed and new models keep getting released by Microsoft, but these rely on well defined interfaces and a lot of it is in the kernel mode driver framework (KMDF). A detailed history can be found here: https://msdn.microsoft.com/windows/hardware/drivers/wdf/kmdf-version-history https://msdn.microsoft.com/windows/hardware/drivers/wdf/kmdf... The user mode driver framework is similar. I'm not going to go through the rest of the subsystems, you might want to review this document: https://web.archive.org/web/20160113113554/http://research.microsoft.com/en-us/um/redmond/events/wincore2010/Dave_Probert_1.pdf https://web.archive.org/web/20160113113554/http://research.m... So... sure, things have changed over the years but they most certainly aren't radical enough to stall development of ReactOS.