When I worked for BestBuy the store had a mainframe. I thought to myself ,"what the hell do they need a mainframe for to run a store?" A region or a district I could understand, but most of the tasks for running a store could be done from a decent Windows box. I figured they bought a lot of them for cheap and needed for them to do something so printing SKUs twice a week was what they were good for.

When I got to university the guy that ran the IT department for Walmart gave a presentation on how they got real-time data on each store.