For the banks to put linux on their ATM's they would have to buy new ATMs from a different vendor that uses linux (if one exists), which would be very expensive.
I could've learnt a lot more about Linux.
You guys crack me up with your suggestion that they "install linux" on their ATMs. Those ATM's are most likely made by Diebold, and the banks have no choice over what OS goes on them. Diebold used to use OS2 but switched to Windows when support for OS2 went away. I beleive the new ATM's by Deibold run XP Embedded.For the banks to put linux on their ATM's they would have to buy new ATMs from a different vendor that uses linux (if one exists), which would be very expensive.