HTML and CSS Reference
An overview of the WinrT ApI
With Windows 8, Microsoft makes an important move. This move is ultimately the reason for the
two souls of Windows 8 and the need to distinguish between Windows Store applications and all
other applications. Microsoft Windows 8 replaces the underlying layer through which the core of the
operating system functions and is exposed to user applications.
The new infrastructure that backs up Windows Store applications is known as the Windows Runtime.
The Windows 8 stack
In Figure 5-2, you see the Windows 8 Runtime stack at a glance. The diagram shows how two parallel
stacks can live side by side to support two different application development models—one centered
figure omits the third stack we mentioned earlier that is centered on C++ and XAML.
It is key to notice that both stacks rely upon the services of the WinRT application programming
interface (API) which, in turn, is serviced by the operating system kernel. The kernel of an operating
system is the core engine that provides basic functionality. To use a car analogy, if the WinRT API is
the engine, then the kernel can be assimilated to the collection of essential components the engine is
FIGURE 5-2 The Windows 8 stack.
The gray boxes indicate which parts of the stack are interesting for the scope of this topic. You'll
like. Your interaction with the underlying operating system will actually be mediated by the WinJS