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

[Paul Koning via cctalk]

> On Mar 2, 2026, at 9:49 AM, Carey Schug via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
> BOS and BPS for the 360 were on punch cards.

That would make sense, since those were basic OS for machines with no tape or 
disk.

> the Pitney bowes, later Raytheon, 440 had an operating system on paper
> tape.  they had a large spool with a biderectional high speed tape drive.

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