The doit shell file cd's to $H, which refers to the directory that contains the hello world test. The console is a raw com port. Certain test programs behave differently with different com port speeds. To test the programs, it is required that you hook up a terminal ( or minicom or procomm it doesn't really matter ) to the comm port of the target hardware. You must ensure that the baud rate, parity etc is set properly. This is done on the target hardware within interns.s . ( Set your terminal emulator to match. ) Currently, the settings are 9600,8,n,1 . The format and layout of the file interns.s is taken from the intel ApBuilder software, freely distributed by Intel. Some easy macros ( SetExRegByte and SetExRegWord ) are basically lifted from the Intel macros. Similarly for the names of the IO ports. This "port" begain with the forceCPU bsp. Hence I am sure that there is some real trash that is not appropriate. For example the act of copying the Interrupt Descriptor tables and Global descriptor tables "into our space". ( in start.s I think ) Erik