Hey,
I understand that much but what if I want to load program? Assume I already have access to the file (disk and filesystem driver present) how can I load bare instructions in "instruction segment" from say a Mach-o file. basically what want to know is how you go about creating an task given the bare instructions as in a file.
In such a case you do whatever you'd need to do on any other OS as well. You use a binary loader that interprets the binary format, finds out which sections of the binary should be placed where, sets up the memory layout, and determines the entry point of the application. There is an ELF binary loader already coming with L4Re, you might want to go through it and the Mach-O binary spec if you wanted to have a Mach-O binary loader.
Bjoern