[bogomipz]

Thank you for the wonderfully detailed response I really appreciate it. I have one follow up question to your reply which is who maintains Amadeus, Sabre and Travleport? Are these consortiums similar to MasterCard and Visa then? I'm guessing these are all big mainframe operations?

[namdnay]

You're welcome. Amadeus, Sabre and Travelport are now independent companies. But indeed all of them were initially parts of airlines, that were then spun off.

Sabre for example was originally American Airlines' system, and Amadeus was initially created by a consortium of european airlines in reaction to the threat of american hegemony on this market. They are now far more profitable than their parents :)

They were all originally heavy mainframe operations (IBM TPF - which was quite an impressive system... in the 80s), but there is a transition to modern architectures. Amadeus have completed the transition to Linux boxes, Sabre are still ongoing. They both have some of the biggest civilian data centres in the world