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The Men Who Fix the Internet
An anonymous reader writes "Remember all those undersea cables breaking? PopSci.com introduces John Rennie, who '... has braved the towering waves of the North Atlantic Ocean to keep your e-mail coming to you. As chief submersible engineer aboard the Wave Sentinel, part of the fleet operated by UK-based undersea installation and maintenance firm Global Marine Systems, Rennie — a congenial, 6'4", 57-year-old Scotsman — patrols the seas, dispatching a remotely operated submarine deep below the surface to repair undersea cables.' The article goes on to outline the physical infrastructure of the Internet, including some of its points of vulnerability."
Dragging an anchor isn't something you try to do. It's something that happens when the weather is more then the anchor can handle. Better to drag the anchor then to rip the anchor capstan off the boat. Funny how boats and cables both anchor near the shore ... you know, that place where people are.
You anchor down if it's stormy and you can't escape it. With strong currents or wind you might end up dragging the anchor. That's the only explanation I have.
There are enough satellites up there that we can get *some* communications without cables. Those satellite links suck at the best of times, though - if nothing else they have horrible latency, and can't approach the huge bandwidth of an undersea cable full of optic fibres. Just like in your own apartment, wireless is cool for convenience and for when you have a kitten (or fishing trawler) messing with your wiring, but cabling is always faster and better for fixed installations.
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
One HUGE propblem with satcoms, and why satcom pretty much went away for telephone - latency. A geosync sat orbits at 26200 miles (roughly), making a 2 way trip (up and down) a 52400 mile trip from point A to point B, or making it take a tad over .28 seconds. Now wait for your ACK to come back, another .28 seconds, and think about what you have. A slow, limited bandwith link. Generally, Satcoms have become used in one way "broadcast" type trasmissions (send the 30 minute TV show up, don't worry about the 1/4 second, as they are recording on the toher side) OR "Ad-hoc" communications, where you don't KNOW where the other station will be (a ship on the ocean, a TV news crew that is in Akron today, and Iowa next week, and even then, they try to keep the signals off the birds unless it's breaking news. You try to get it to a local affiliate, and land line it back)
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
... and the article couldn't even get that right.
Blech. For much more interesting reading, check out this classic:
Mother Earth Mother Board
You anchor down if it's stormy and you can't escape it.
That's pretty much it. The last thing a skipper enjoys is to be pinned against a lee shore by a gale. If he can't get into the safety of deep water, dropping the hook is sometimes the only option. Sometimes, if his hook is too small or if its chain is too short for the wind/current load, it'll drag. It's not a fun situation to be in; I've been there.
> Sometimes, if his hook is too small or if its chain is
> too short for the wind/current load, it'll drag
The interesting thing is that it's the weight of the chain that holds the anchor, not one of the flukes catching on something. A successful anchoring is when the anchor is on the bottom, in mud, and there are xx fathoms of chain piled up on top of it. Leastwise, 'twas so in my day.
Once we were getting underway for a dependent's cruise and the CO was on the bridge and shouted "let's go!" and clapped his hands. An alert bridge talker heard him, misunderstood, and dutifully relayed "let go!" to the foc'sle. So the anchor was dropped about 100 yards off the pier (at 4-5 knots) and fun times ensued. The CO handled it well and had the grace to make a sheepish announcement a few minutes later on the 1MC. Good times.
The Army reading list
Iridium puts its satellites in low earth orbits to avoid the latency issue. It's geosynch orbits that are up high. But I do remember making telephone calls that went over geosynch satellite back in the 80's, and the latency is really annoying - you're never quite sure when the other person is finished talking, so you end up talking over each other, and having awkward pauses. When fibre became common, most telcos stopped using satellite.
What was once true, is no longer so
Correct. I forgot to bring up the Low Earth Orbit Sat Phones (aka Iridium), which is another kettle of fish. The big problem there is limited channels, again, your not going to have the kind of bandwith you need for serious internet (note, I said serious, like multiple OC3 stuff).
Interestingly, NATO, with all their Sats, and Iridium (Remember, the US Military basically keeps them in business) is re-looking at HF radio comms. Ultra high speed 24 bit DSPs, and other technologies are making them clearer and more reliable (less dependent on operator skill), and they have the advantage of working when you have a limited sky view
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
preventative maintenance
For God's sake, it's preventive maintenance. Having served in the Navy, I can't count how many times I've seen this mistake.
To address the issue at hand, the maintenance is done properly in the vast majority of maritime cases. Shit still happens, as Mother Nature tends to get rather moody several times a year.
512 MB RAM, 20 GB disk, 200 GB transfer, five datacenters. $19.95/month.
"What do other parts of the world do ?"
The same thing
"Are hubs (fiber locations?) for cost savings, lazy design, best design for a shareholder when burning tax payers re nation building, collusion between telcos, easy NSA access ?"
All of the above
At some point you need to connect network E from Elbonia to network P from PHiliBelphia and also networks a through z. This starts to get expensive real fast no matter how you do it. Doing it in one place lowers cost (hub) but focuses for a point of failure. As the article said - you can't get away from this. I like how they said the best way to prevent cascading network damage is to shutdown the "nearest" hub connections to the failed point to minimize the damage - like they do when the electricity transmission network or a generator goes off somewhere. It isn't optional and can't really be worked around - if you want random person E to get stuff from P then you need interconnects somewhere. Yeah you could do it with a lot (a real lot) of little interconnects all over the place - just don't and service them as your staff will always be in the field.
The Singularity is closer than you think
Quant
Don't be so harsh. In English it's "preventative" maintenance. I would guess in US English it's "preventive" (I didn't know that, so thanks)
O RLY ?
That would be 'didna'. Dinna means don't. In fact let me fix that for you, Glaswegian style:
I didna baw when ma da was chibbed fur nickin a pig, but am bawlin now :(
Getting chibbed is of course being stabbed with a sharp implement, but it works better since we haven't hung anyone in Scotland for quite some time.
which is totally what she said
This article details the building of the first transatlantic cables in the 1850s & 1860s. Definitely trickier to repair back then (lay another one)...
I’m old enough to remember 16K of memory being described as “whopping”
They are a printer vendor.
You are correct, grasshopper. The speed at which light or radio waves propagate in a medium is determined by that medium's index of refraction, which (as you stated) is 1 for a vacuum. A typical value for fiber is 1.47, so the signal in the fiber travels only 68% as fast as the radio wave in a vacuum. The distances involved with geosynchronous orbits, however, make up for that slower speed. In the time it takes the radio wave to reach the satellite (35,786 km / 300,000 km/s = 119 mS), the fiber signal could've circled the Earth 1.2 times (119 mS * 204,082 km/s = 24,286 km (Diameter of the Earth is approx 20,000 km).
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Time-domain reflectometry using a Time-Domain Reflectometer.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Hell, the average telephone exchange, if you nuked everything around it, would be giving dialtone and DSL to the skeletons for at least a week, probably more depending on how much diesel is in the tanks.
During the northeast blackout of '03, all of the utilities went out. Street lights, traffic signals, all went dark. Cell phone towers went out. There wasn't enough water pressure beyond 5 stories. There was gas, but no starter. But there was still a dialtone through the landline. And we could still make calls out, if our phone didn't require an external power source. Most of the handsets we use are cordless, but we have several of the simpler phones lying around for such emergencies.
"If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
Wullie disna baw.
Wullie greets. Greets like a bairn inty his whisky mac.
Factory freezer-trawlers are still in wide use. Portugal and Spain are always fishing on the Flemmish Cap of the Grand Banks just outside of Canada's 200 nautical mile limit.
http://en.wikipedia.org/wiki/Flemish_Cap
52 52'23" W 47 32'07" N