Hi, what i'm trying to do is to access floppy drive and read some data. To do this i'm using CreateFile p/invoke with filename "\\\\.\\A:" (that's because Filestream.Open doesn't support floppy device reading) and Filestream.Read with handle parameter returned from CreateFile. Everything works perfect except when i try to seek position using Filestream.Seek, it returns with IOException - invalid parameter. I've tried with p/invoke SetFilePointer from win32 but it returns with the same error (ERROR_INVALID_PARAMETER). Funny thing is that the same function works in pure c++ code... Does anyone know why this is happening and how to fix this?