These functions provide high performance, low level video routines designed for text mode applications. Routines include basic windowing, text output, cursor manipulation, etc. Since these routines have been written in assembly language and meticulously optimized for both speed and efficiency, they race at the fastest speed possible on your computer while adding very little to the size of the resulting executable file.
Source code is available.
No response from batch files, BEEP from batch file, clear NumLock, etc. Source code is available. Very simple DOS menu program. Customize by editing simple text file. Well who knows.