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How Mobile Phones Work Behind the Scenes
adamengst writes "We seldom think about how our mobile phones actually work, but in this TidBITS article, Rich Mogull pulls back the covers and peels away the jargon to explain why text messages work when voice calls are dropped, why your battery lasts longer in some places than in others, why you're not allowed to use phones on airplanes, why you can be notified of a voicemail message when your phone never rang, and more."
Whilst that may be a perfectly valid reason to you, the real reason is that the airlines just haven't figured out how to charge for it yet.
They will soon:
http://www.guardian.co.uk/news/blog/2008/sep/25/ryanair.mobilephones
which includes a classic quote from Ryanair boss Michael O'Leary:
"If you want a quiet flight, use another airline."
How do mobile-phone servers distinguish between a switched off mobile phone and a one that is 'out of reach' of the mobile towers ? I never understood how I get those two different messages. What mechanism is used to differentiate between a switched off phone and a one that is out of reach ?
And yet still cost more than an actual call...
http://www.tidbits.com/about/in-use.html Emperor The machine emperor.tidbits.com, also known as www.tidbits.com and just tidbits.com, is our main server. It does basically everything for us now.
Dual 1.33 GHz Xserve G4 - [Our server, sic]Emperor runs on a normal dual 1.33 GHz Xserve G4 (2 GB of RAM). Emperor is still running Mac OS X Server 10.2.8, which came with it and handles the load just fine, so we haven't had any reason to upgrade.
Web Crossing - The server software that powers all of our Internet services is Web Crossing, from the company of the same name. Web Crossing can do just about anything, since it backs up its built-in Web, FTP, email, and NNTP service with plug-ins that add mailing lists (also accessible via the Web and NNTP), RSS support, weblogs, wikis, and much more. A lot of this is possible becuase at its heart, Web Crossing includes a high-performance object-oriented database and not one but two programming languages for creating dynamic sites. Web Crossing is the software that Apple uses to host their discussions.
My experience from flying in private aircraft (both prop and VLJ) is that rarely do you get service above 6000' AGL. You get blips to about 10000' AGL so a text message can come in or out, but a phone call is pretty much out of the question.