What constitutes a “next-generation” data center? To understand, it’s worth looking back in time.

Back in the old days - 20 years or so ago - a data center was a "glass house" - a room full of IBM mainframes, DEC minicomputers, and their attached storage subsystems. Users typically connected to these machines by local terminals. By necessity, then, data centers were usually located physically and geographically within corporate and administrative headquarters (where most employees worked). And data centers contained a relatively limited suite of gear: computers, storage systems, a terminal server, and a massive HVAC system.