I can say that the article doesn't explain it very well. Since CERN has been calling the sites "Tier", this terminology has become a buzzword, and everything is a Tier (the managers call their services "Tiered" just to make them sound important).

Tier0 and Tier1 are well described by the article. Tier2 are mostly computing clusters, with of course big storage, but they're mainly for analysis. Tier3 are like Tier2 but not really. They are "uncertified" Tier2 in the sense that they do not strictly adhere to the Tier2 standards in terms of middleware and configuration and policies.

Tier4... never heard of that, I think the buzzword Tier backfired and they're calling their desktops Tiers. When I started managing the Tier3 we did not even call it like that... it was just a cluster.

TFA says they use 48RU, and each cabinet uses 14.4 kW (60A) which in my opinion is not that impressive: you just need 3 phases at 20A, 240V.

As for cooling, you can easily get away with no water-cooling if your hot aisle confinement is well done. From the pics it is just Dell's 1U servers, and if you fill one 48U rack with those you do get to 14.4kW. But not all racks are for number-crunching, you have racks for storage, control and network, and those make less than 8kW.

The problem is not powering those things, but more cooling. With a good hot-aisle or cold-aisle confinement you can go up to 15kW/rack, but depending on the air volume, you're quickly screwed up if the cooling fails.

I have been traveling in Europe and especially in Italy and I can tell you the plugs are not really like that:

- what they call the "Euro Plug" is not a standard for real equipment. You'll never find for example a desktop computer with that plug. You can find mobile phone chargers and small equipment. There is no wall socket for this plug (except maybe still in Italy), as it fits the "real" Euro socket and the Swiss and some more.

- the real Euro plug is like the French, Czech or Italian for example (like this one: http://www.more-shop.co.uk/images/EUpccable.png). Of course some Countries in Europe do not comply (Switzerland for example: http://www.travelplugs.co.uk/products/uk/sw/sw1_200x150.jpg)

- the Italian plug they mention is not in use anymore and is being replaced by the above European plug. So Italy has 2 types of sockets (used to have 3).

- they forgot to mention that "hybrid" wall sockets exist in Europe. For instance you can accomodate both a Swiss plug and a (real) Euro plug, or in Italy, all the 3 types of plugs onto the same socket (it has both a ground pin and hole).

Article is mostly chauvinistic crap. I've been living in Europe, working there, in strict contact with electricians in several Countries. It is a mess and the standards change in space and time, you cannot just google "Euro plug" and pretend you know.

FYI the simulation is running on this machine: http://top500.org/system/7388

Actually most of the PS3 games take advantage of the PS2 emulation -- not that they would run on a PS2, of course.

The PS3 appears having only 6 SPUs when the Cell really has 8. The 7th is used as a hypervisor to run PS2 games efficiently and the 8th is "disabled". The hypervisor is what saves games developers -- they can take the shortcut but are not fully using the GFlops. But: consoles get sold, and part of this money is invested in developing new chips which are not only used in newer consoles but also in supercomputers like this one.