[Windows Phone 8 Q&A, Help & Troubleshooting] GoodDayToDie:
There are so many factual errors in the above post I don't even know where to begin...

"Native" in this sense refers to apps written in a language which gets built ("compiled" although that technically involves compiling, assembling, and linking) directly into machine code ("0s and 1s" is a silly way to describe it, since *everything* on a computer, from programs to plain text files to MSIL or Java bytecode are all binary). Machine code means a binary sequence that the processor can directly execute. This is also referred to as native code, i.e. code which executes on the processor without needing an intermediary layer.

Although technically "native" and "unmanaged" mean different things, the difference is not what you think it is, and it's not very relevant to this discussion. It's entirely possible to have a native managed language ("D" was supposed to be such a thing; I'm not sure to what degree managed C++ qualifies) and to have intermediate-compiled unmanaged languages (you could, for example, distribute unmanaged programs compiled to LLVM bytecode; some systems might actually be doing so). However, MS themselves typically use "native" to mean "not managed", as evidenced by things like debugger modes.

These days, almost everything gets JIT (Just In Time) compiled to machine code even if the build tool didn't produce native machine code itself. This applies to .NET code (gets built as MSIL), Java (gets built to Java bytecode or Dalvik bytecode if on Android), JavaScript (doesn't go through a build process at all, but modern browsers JIT compile it to native before execution nonetheless), and many other languages. Interpreting is slow and requires a lot of memory overhead as well (you have to run the interpreter in parallel with the program actually being executed).

Although it is possible to invoke managed code from native code (only a little messy) and vice-versa (very common, see P/Invoke or COM interop for .NET, or JNI for Java), this should not be confused with them being the same thing. Yes, by the time they reach the CPU instruction decoder they're the same, but the process of loading the program, and the "runtime" environment that it interacts with, are very different indeed. Managed code uses a memory manager (hence the name), which takes care of things like defragmenting and freeing memory (via the garbage collector). This fundamentally violates a number of assumptions common to unmanaged code, such as that the address of data in memory will never change on its own, and that once allocated, a block of memory on the heap remains reserved until manually freed.

Another important difference is that managed languages must use abstractions of function pointers (for example, .NET delegates). In native languages it is possible (though generally unwise) to specify an absolute address (0x040C7F06 or some such) as a function pointer, and call that "function" (which results in the processor attempting to execute instructions starting from that memory address). In practice, this kind of thing is almost never done in PC software; it's bug-prone, completely un-portable, incompatible with security features like ASLR, very difficult to debug (this is the kind of thing that malware might use to make reverse engineering it harder), and there's typically no reason at all to do so.

However, the fact that it's *possible* is a Big Freaking Deal for somebody looking to work around a runtime security check. Consider this: Sliverlight on WP7 doesn't allow arbitrary LoadLibrary (or Assembly.Load, or similar) calls. The APIs available to your app are the ones included in its DLLs, and the ones in the Silverlight for WP7 runtime libraries. Even though the desired functions exist on the OS, and are even linked into program memory, you can't call them because there's no way to get a delegate for them. Now, compare this to native code, where you can literally just scan the code section of your app's memory until you find the entry point for the function you want, then treat that address as a function pointer and jump right into it.

Now, to be fair, I haven't actually written any official WP8 C++ yet. However, I can tell you that the trick mentioned above works just fine in Windows Runtime C++ on both Win8 and Windows RT, which are also supposed to lack APIs like LoadLibrary, and I therefore suspect it will work fine on WP8. Some experimentation is due, in any case.