Refrigerated vault

In the late 90-s, newly emerged IT outsourcing companies could be located anywhere. The first office I was working in was just a room in a children's sport school. The cool thing about the room was the speed of the internet connection. I could download stuff at ~20KB/s. (That was in 1999). A room next door hosted a big ISP :)

The second office was more interesting: the server room there had a pre-installed air conditioning and cooling system. It was installed by the previous tenant. The cooling system could easily get the temperature well under -20C. Also there were thick walls and doors there. Anyone can guess who was a previous tenant?
I will update the post with correct answer in a few days, if there are no right guesses (that is very likely as my ex-colleagues do not read my blog)

Upd: max630 guessed right!