Hail to IBM's OS/2 still used by a lot of banks to this day - oh and I still have an OS/2 machine and a few Linux machines and AiX ..
Sad to say we don't use OS/2 internally* any more although I dare say theres some servers lurking about ..
Sadly on my everyday workhorse machine I still reluctantly have to use XP


*Internally - as in inside the bigblue company that designed and launched OS/2