Posts by Iain McClatchie

Walking in a WiFi wonderland

Re: Virtualisation

The hardware appears to be 100 Mb/s links to Megafon and Rostelecom and 10 Gb/s link pairs to a dozen or so spots. I did not see the spread to the WiFi access points described, but presumably they used standard many-port Gb/s switches for that, which generally run a couple hundred dollars each.

I agree that there are no conceivable scenarios in which a 54 Tb/s switch can be overwhelmed by a few dozen 10 Gb/s links. I would expect the front panel looks rather sparsely populated.

I'm surprised that the internal bandwidth is provisioned for two orders of magnitude more bandwidth than the outgoing links. Perhaps they are schlepping uncompressed 4K video to their local editing booths? That video can get pretty large.

The other thing that surprised me was that text-based Twitter used more bandwidth than several video services. I would have expected even a few Facetime video links to generate more traffic than every Sochi visitor simultaneously banging on Twitter.

Leaping SpaceX GRASSHOPPER ROCKET jumps 2,500ft, lands safely

So does 1d-VAC require cold gas thrust for roll control? Seems like that would need a bunch more mass, and add risk, as they've had two different unplanned events with too much roll - one of the early Falcon 1 upper stages was lost due to excessive roll, and this latest launch's lower stage rolled too much as they tried to recover it.

Facebook throws servers on their back in HOT TUBS of OIL

But cold isn't fast anymore...

Cold improves transconductance, which used to make logic gates faster.

But cold also increases the threshold voltage, which has a bigger effect these days. So you want your overclocked machine running hot for max speed. This is going to make electromigration even worse though.