And want to know something else? The UI layer was html + javascript and some funky css that ran on a custom modified version of ie6.

Beneath that, to handle fetching of data, comms, navigation, window management and other business logic etc, we used good old .Net and C#.

It was a bizarre setup from a dev perspective but once you got used to it you could crank out new features incredibly quickly as you had a heavily regimented workflow (Usability trumps _everything_ with these machines).

If you open up an ATM you will find your standard run of the mill beige PC inside it and in fact in many of the older machines they _literally_ stuff an _entire_ PC case in there simply laid on it's side.

There is also an extra monitor back there with a little keyboard attached.

The only impressive aspect of ATM's is the engineering that goes into all of the supporting hardware and peripherals such as the stackers, the cash acceptors, the cheque validators, the printers, the recycling cash canisters, the electronic pin pads, the various fraud detection features etc. I found that stuff much more interesting than the dev work I did day to day.