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Wireless mesh at the beach |
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Submitted by sverma on Sunday, May 4, 2008 - 10:07 |
OLPC | XO |
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It was a great day to be at the beach in San Francisco (Apr 27, 2008). Thanks to Jason Stone and Jim Stockford for sparing their Sunday afternoon, we met up at Ocean Beach with three XO laptops. The little green machines attract a good bit of attention. Even before we got started with out little experiment, we had people stopping by to ask questions or just check out the green machine.
So, the experiment was: How far will the point-to-point mesh network on the XOs go in relatively clear RF (radio frequency) environment? At least cleaner as far as 2.4 GHz spectrum goes. We did such a run on campus and got about 600 feet max. or so across two XO units. I suspected that this was because our campus has a lot of Wi-Fi traffic, so the interference alone would decrease the hop length. We also have a lot of foliage, so that would add to the interference.
Ocean beach is right along the Pacific at the edge of San Francisco. I hoped that RF would be cleaner there. So, we got started by setting up the mesh of three laptops (me, Jim and Jason) and then got Jim firmly planted (say, position A) in the thick of beach population to answer questions. Jason and I walked south while pinging Jim's laptop all along. Well, we kept on walking...and walking...and walking. This was definitely way beyond 600 feet. Eventually, we started seeing "host unreachable" a few times, so we stopped. We saw ping times of about 25 to 30 ms. Jason became point B there. I kept walking further south and after a few steps, the pinging resumed with low latencies (3 to 5 ms). I kept walking...and walking...and walking. A quick note about walking on the beach. Walk closer to the water. Its a lot firmer and works well when measuring paces (1 pace approximately equals three feet). Eventually, I started seeing "host unreachable". I called Jim to verify. He was seeing the same. I tried holding the laptop higher up and the pings would resume. Eventually, I stopped at what I thought was the outer limit of pings, marked the spot and took the following picture.
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Ubuntu 8.04: Oh, the miracles! |
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Submitted by sverma on Thursday, May 1, 2008 - 20:24 |
Ubuntu |
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I just finished installing 8.04 LTS on my old(er) Fujitsu Lifebook P2120. Yeah, I'm slow at adoption...by a few days. So, forgive me! Anyway, I had tested the Beta under VMWare so no real surprises there, except the big surprise was with suspend and hibernate. After installing and without further updating, I decided to try out suspend and hibernate features. Well, guess what? They work like a charm. A bit slow compared to Windows XP or MacOSX, but it actually works!!! Way to go Ubuntu!!!
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