Overwriting, saving, using stream. Are they really different?

I want to make a file unusable. Does it really make sense if I overwrite it?

Is there a difference betwe开发者_StackOverflow中文版en overwriting, using stream, saving or just appending text?

^{Note: I want to delete the file afterwards and avoid recovery.}

Appending probably won't help. If you open the file for reading and writing, point to the beginning, and start writing, that probably has the best chance of working (from a high-level language like C#).

You may have to get even lower-level to really do this, otherwise you risk the OS using a different portion of the disk for your new data, defeating the purpose. But I suspect the above should work.