TMRC /tmerk'/ N. The Tech Model Railroad Club At MIT, One Of The Wellsprings Of Hacker Culture.

HomeFortune CookiesJargon File

TMRC /tmerk'/ n.

The Tech Model Railroad Club at MIT, one
of the wellsprings of hacker culture. The 1959 "Dictionary of
the TMRC Language" compiled by Peter Samson included several terms
that became basics of the hackish vocabulary (see esp. foo,
mung, and frob).

By 1962, TMRC's legendary layout was already a marvel of complexity
and has grown in the years since. All the features described here
were still present when the old layout was decomissioned in 1998
just before the demolition of MIT Building 20, and will almost
certainly be retained when the old layout is rebuilt (expected in
2003). The control system alone featured about 1200 relays. There
were scram switches located at numerous places around the room
that could be thwacked if something undesirable was about to occur,
such as a train going full-bore at an obstruction. Another feature
of the system was a digital clock on the dispatch board, which was
itself something of a wonder in those bygone days before cheap LEDs
and seven-segment displays. When someone hit a scram switch the
clock stopped and the display was replaced with the word `FOO'; at
TMRC the scram switches are therefore called `foo switches'.

Steven Levy, in his book "Hackers" (see the
Bibliography in Appendix C), gives a stimulating account of
those early years. TMRC's Signals and Power Committee included
many of the early PDP-1 hackers and the people who later became the
core of the MIT AI Lab staff. Thirty years later that connection
is still very much alive, and this lexicon accordingly includes a
number of entries from a recent revision of the TMRC dictionary.

TMRC has a web page at