Well, sort of. If you had non position-independent code, it would blow out (it would be off by 020). Also, some bootstraps (e.g. the RL, IIRC) were so close to 512. bytes long that the extra 020 was a problem. And it was so easy to strip off: dd if=a.out of=fooboot bs=1 skip=16 I'm not sure that anything actually used the fact that 407 was 'br .+020', by the V6 era; I think it was just left over from older Unixes (where it was not in fact stripped on loading). Not just on executables running under Unix; the boot-loader also stripped it, so it wasn't even necessary to strip the a.out header off /unix. Noel