[cctalk] Re: Operating system, on punch cards?

That would make sense, since those were basic OS for machines with no tape or disk. That's wild, I never heard of a bidirectional paper tape reader. There is something vaguely like that in the original EL-X1 ALGOL compiler. Since the machine (originally) only had 4 kW of memory, it needed several passes. The intermediate object file tape would have the code on it, then a table of library symbol references at the end because only at that time would the list of needed functions be known. The loader needed to load those functions to resolve references, so rather than make two passes over that tape, the tape was read in reverse direction instead. It's rather strange to look at code that interprets a tape read backwards. paul