Apropos of Steve Johnson's evocative description of JCL and other pre-Unix OS interfaces, doing legwork for Multics I ran the following experiment on a lot of then-current time-sharing systems. As a model of creating and installing a new compiler, I used a very short Fortran program that simply copied its input to its output, stopping after finding END in column 7 of the input. The drill was compile the program run it, using its own source as input compile the freshly made output file This failed on every system I tried it on, though local experts could intervene with magic to overcome the gratuitous file-type distinctions that typically got in the way. Dartmouth's DTSS came closest, but inexplicably, even to the gurus, it had a special prohibition against a program reading the source from which it was compiled. Incidentally, my favorite manifestation of JCL-like mumbo jumbo was the ironically named FUTIL control card in GECOS. Doug