“After our coverage of London’s Oyster card, which uses Linux
for its online payment system, we had a response from Richard
Stallman, head of the Free Software Foundation.“The original article was Linux Opens London’s Oyster.
“The GNU system (often called ‘Linux’) has been developed, since
1984, for the sake of computer users’ freedom. Ironically it is now
the basis for a system designed to smother the freedom of the
people of London, through online payments to Oyster cards.