This story says a lot about the ITS ethos.
On the ITS system there was a program that allowed you to see what was
being printed on someone else's terminal. It spied on the other guy's output
by examining the insides of the monitor system. The output spy program was
called OS. Throughout the rest of the computer science world (and at IBM too)
OS means ‘operating system’, but among old-time ITS hackers it
almost always meant ‘output spy’.
OS could work because ITS purposely had very little in the way of
‘protection’ that prevented one user from trespassing on another's
areas. Fair is fair, however. There was another program that would
automatically notify you if anyone started to spy on your output. It worked
in exactly the same way, by looking at the insides of the operating system to
see if anyone else was looking at the insides that had to do with your output.
This ‘counterspy’ program was called JEDGAR (a six-letterism
pronounced as two syllables: /jed´gr/), in honor of the former head
of the FBI.
But there's more. JEDGAR would ask the user for ‘license to
kill’. If the user said yes, then JEDGAR would actually gun the job of
the luser who was spying. Unfortunately, people found
that this made life too violent, especially when tourists learned about it.
One of the systems hackers solved the problem by replacing JEDGAR with another
program that only pretended to do its job. It took a long time to do this,
because every copy of JEDGAR had to be patched. To this day no one knows how
many people never figured out that JEDGAR had been defanged.
Interestingly, there is still a security module named JEDGAR alive as of
late 1999 — in the Unisys MCP for large systems. It is unknown to us
whether the name is tribute or independent invention.
