Tony Duell wrote:
> The same set of books describes the train descriptor system used on the
> London Underground. It consisted of a drum with 4 rows of pins on it.
> Each pin could be in or out. The drum rotated past a 'write' device that
> set the pins to one of 16 states corresponding to 16 different types of
> trains. A 'read' device consisting of contacts/switches rotated inside
> the drum, detecting the postitions of the pins in a given column. It was
> an electromechanical version of the classic circular buffer with read and
> write pointers... If anyone's in London and wants to see this device,
> there's one in the London Transport Museum, BTW.
An excuse to visit England at last. (Wales, Scotland and Ireland have
been my only reason to consider crossing the Atlantic -- the "roots" gig
-- haven't done it yet anyway.) I know damned well there's nothing like
that over in the New York Subway Museum in Brooklyn.
--
Ward Griffiths
Dylan: How many years must some people exist,
before they're allowed to be free?
WDG3rd: If they "must" exist until they're "allowed",
they'll never be free.
Received on Tue Jan 06 1998 - 22:32:07 GMT