Find Darren Atkinson's brilliant bit-banger routines here: https://sourceforge.net/p/toolshed/code/ci/default/tree/hdbdos/dwread.asm#l357 https://sourceforge.net/p/toolshed/code/ci/default/tree/hdbdos/dwwrite.asm#l212 (see top of files for usage) Regards, Tormod