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 1994 -- in the Unisys MCP for large systems. It
is unknown to us whether the name is tribute or independent
invention.
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