Global Distribution Systems (GDS) started in the 1950s to automate airline reservations which were previously done with index cards. The first GDS, SABRE, was created through a partnership between American Airlines and IBM in 1960. There are now four major GDS: Amadeus, Sabre, Galileo, and Worldspan. GDS allow travel agencies to book flights, hotels, and other travel services. However, airlines have sought to reduce their reliance on GDS and associated fees by establishing their own direct booking channels. This has led to increased competition and new entrants trying to replace the traditional GDS model.