Originally Posted by
Elkvis
I don't really understand why you want to combine assembly language with C#/.Net. To me, it seems like a fool's errand. If you really want to do this, you could write your assembly language as inline assembly in a C++/CLI project (if it will let you), to produce what they call a "mixed-mode" assembly, which contains some native and some managed code. You would then reference that assembly in your C# project.
Another option would be to make a fully native Win32 DLL containing your code, and use P/Invoke to call a function in it.
It still doesn't make sense to do that, because the C++ compiler has gotten so advanced (since the DOS days), that it can probably generate better machine code, from C++, than your hand-written assembly language. I'm not trying to start a fight or belittle your abilities in assembly language, but C and C++ compilers have come a long way in the last 20 years. In my opinion, it would be better to just write an optimized C++ function to do what you want with the file.
You're likely to get some raised eyebrows, and perhaps even some unkind words, as a DOS programmer, when you start telling people how their access methods "should have" been written. Tread lightly here.