PARS

PARS (Programmable Airline Reservation System) is an IBM proprietary large scale airline reservation application, executing under the control of IBM's ACP (and later its successor, TPF). Its international version was known as IPARS

In the early days of automated reservations systems in the 1960s and 1970s the combination of ACP and PARS provided unprecendented scale and performance from an on-line real-time system, and for a considerable period ranked among the largest networks and systems of the era.