I just thought to myself that, my goodness, our students don’t even know how a mainframe computer looks like? Not even seen anything from photos or pictures? Mainframe computers are no doubt getting quite rare these days, so it is not surprising that few people have actually seen the real thing with their own eyes. But I’d imagine at least a computer science student would have some impression from pictures in books or on the Internet. (Check Google images for some impressions.) The last mainframe at my workplace, an IBM 3090, was decommissioned and removed before year 2000 (I think).
It’s just amazing how technology has progressed. When I started work, VAXes were still in operation. The trend at that time was for things to become smaller, more compact, consume less electricity and generate less heat. Then, when high performance cluster computing became more prevalent, some of these trends started to reverse. Our Data Centres started to demand more electricity, and cooling became a major challenge again. More than 10 years ago, we needed 32A 3-phase power supplies, then it became alright to cut down to 32A single-phase power (and indeed many commercial data centres simply standardize on 16A single-phase power), but today we are back to 32A 3-phase and even 63A single-phase power supplies. Data Centres used to have lots of plumbing (to carry chilled water or refrigerant for cooling mainframe computers), then CRACs (computer room air-conditioning, which are just expensive air-cons that can control temperature and humidity) became standard, and guess what? Today people are talking about water-cooled CPUs again. Indeed, my latest Data Centre now has an underfloor plumbing system carrying chilled water into liquid cooling racks.
Another student passing by gave an estimate that this contraption (the isolation transformer) weighed maybe 1000kg. Yes it is heavy, but no, nowhere close. More like 4 tons perhaps. Ok, I admit, estimating weight is not so easy. Although most people know that metal is heavy, they may not appreciate how much heavier a humongous chunk of metal like this would weigh. (Interestingly, I was surprised at the reality of how heavy water is. You know 1 cubic meter of water weights 1 ton? This is from physics lesson in school, yah? Just imagine, 1 cubic meter is just 1m x 1m x 1m only, and that little cube is 1 ton!)
Well, anyway, we were replacing a 1.2MVA isolation transformer. It took our movers all of 3 hours to remove the transformer above. Just move on same level, no steps, under 100 meters, rolling all the way. Imagine the effort to push 4 tons. Okay, some of the delay was due to floor protection (the need to lay plywood and steel plates to both protect the floor finishing and distribute the load).