"in case of a large scale disaster the Internet/data centers might be down" This relevant comment by Alex begs the question, "how long (in the "average disaster") does it take to reconstitute necessary services? What has been recent experience?

To bring it home, when the Big One comes to southern California, for how long will the rest of you be deprived of the insightful posts of those of us living in the affected region? I know it will be tough,but hang in there....

The Internet was originally designed to be robust and have some capability to route around damaged areas. Once the "last mile" services (DSL, cable, business-class connections, mobile wireless) are restored in many types of large-scale disasters there's a good chance that the "backbone" (connectivity beyond the last mile) will be up or will come up fairly quickly.

Presumably Internet connectivity will be unaffected outside the disaster zone, and presumably most larger services will be designed robustly with multiple datacenters in multiple geographic region.

I'm optimistic that most larger companies based in earthquake-prone areas, for example, have datacenters in other locales.

Do you have a backup Satellite Internet Service Provider in California? A Solar PV electrical Supply for the Satellite Data Modem and wireless broadband router (a VOIP service could be added also for international calls etc) would be easy to set up.

In the UK for example;

https://www.satelliteinternet.co.uk/

I have my e-mail hosted externally at a place called aiso who advertises they are a solar powered data center. So they should stay up for a while.

Your last mile connection to the internet depends on who you have for your local utility. For example local phone service here was bought out by AT$T a while back so you have maybe 50% reliability even when there is no disaster. We switched to a local cable company who keeps the service running and I've user the power companies web site to report my power being out.

The original context of the question was around access to important data. I use the internet to sync data to and from my phone/tablet/laptop but run my own server at home. Since my data is a copy on all three devices and the server its accessible from any of those weather they can get a connection or not. The network connection simply keeps changes in sync automatically so if I update a phone number or something I don't have to manually copy the doc to all my devices.

In the event of a natural disaster, cell phone service is remarkably resilient if it's not overwhelmed by people calling their relatives to tell them they are alright. That's why SMS texting in a disaster is always almost more reliable than trying to actually call someone.

Cell phone towers typically are built very well, and have sufficient battery/generator backup to keep them running for up to 48 hours after losing main line power. As long as the fiber connection to the shack remains intact (and that conduit is designed to flex quite a bit), cell phone service will be there.

There's also portable "Cell Phone Trucks", that can roll into an area and provide cell phone services in the event of a major disaster as well. These trucks have Satellite uplinks and masts that can provide basic cell phone coverage as well.

"Typically" is a key word. In the case of my home, the cell tower is wired into the local phone company's "shack" that controls the switching for our neighborhood.

So, when that "shack" has no power, both the POTS (land line) and the cell tower goes out. When the power comes back, they both come back. And no 48 hour battery back up---maybe 1 or 2 hours.

Generator? Yeah, during the last extended outage, a guy from the phone company showed up in a pick-up, off loaded a portable generator, hooked it up into the "shack" and we were back up operating, until the generator (about 12 hours) ran out of gas.

Eventually, he would come by and refill the gas tank of the generator.

"Cell phone towers typically are built very well, and have sufficient battery/generator backup to keep them running for up to 48 hours after losing main line power. As long as the fiber connection to the shack remains intact (and that conduit is designed to flex quite a bit), cell phone service will be there."

thanks for that info. I didn't know that. it definitely sounds like the weak link in the system is the local phone company, and not the towers. after a major quake, I wouldn't expect that anyone would show up at the company anyway.

In LA, I am expecting phone service to be down for weeks, and maybe months. that may be a very pessimistic outlook.

If the State of California and the cell phone companies really got their ACT together, it sounds like some very good things could be done. The cell phone system could be made much more robust after a major earthquake.

pETE

We had the benefit of a day without power here yesterday. It was a planned outage to replace some underground powerlines. I was able to get most work done early and since I knew this was coming, batteries/cellphone were topped off. Power goes off and my laptop continued running as always, but without connectivity I shut it down; I turned off the iPad too. I really prefer having IT stuff that can handle a power outage without negative results -- no data loss.

When the power dropped off, I lost ethernet to the laptop, WiFi to the iPad and the network extender for the iPhone (from 5 dots (bars) to 1). I was limited to using the cellphone for internet with a 1 dot signal, something to be avoided. I could still make calls but the battery seemed to drain faster than usual. By the time power was restored 7 hrs later, the phone went from 100% power to 57%. Cellular data is normally turned off; does having cellular data activated add to battery drain even if you aren't surfing? Or does the phone need to work harder maintaining a connection when the signal is weak?

Web pages these days are graphic intensive; over WiFi some pages are slow, it takes an abnormal amount of time to open those pages over a 3G connection. Normal surfing is out of the question, so I stopped surfing and only used one of the apps to download specific data. That may have helped save the battery for incoming calls.

If this had been an unplanned outage of unknown duration, I'd have looked for a better signal. To save battery I would have disabled cellular data (as it is now while I'm getting good WiFi). During a real outage, finding a Starbucks or other hotspot out of the area is an option. If I did that I'd take the iPad for data, email, et al, and not use the tiny display on the phone.

Are there any other strategies to consider when staying home is not required?

BTW, despite all those iDevices mentioned above I am not getting an iWatch (it's a bridge too far imo). The iWatch is advertised as being incredibly accurate (50 milliseconds), but as I understand that's because it is constantly updating itself to your iPhone which is constantly updating to the web. To me that is not a timepiece, it's just a remote display.

I'm currently wearing a CountyComm Maratac SR-3. It's waterproof to 10 atmospheres (300'?) which isn't much for a diving watch but should be good enough for a short swim. Since it relies on body movement to wind itself, I wore it for 30 minutes before setting the time and so far it's within a second of my timing source (WWV). A 3 hour trial is not a great test for accuracy, but it seems to work; I'll check it again in a couple days. (no CountyComm affiliation other than as a customer).

When the big one hits all those iWatch wearers had better hope the cellular system keeps humming and their iPhone has a signal, because the remote time display on their wrist relies on that chain of connectivity to give you accurate time. Once the signal dies, that 50mS accuracy will start to degrade. How accurate is an iWatch without a cell connection?

very good point on the last post.

in an emergency - do we really need wideband?
wouldn't a simple text message do a LOT of good?

there ought to be a special cell-phone based emergency system that only uses text messages. no voice, no images. simple text only. that would be a really great idea.

Pete

Are you thinking something other than text messaging that all the kids do and "don't text while driving"? There are maybe two people who send me texts but it works well. Short sentences, no embellishment or pleasantries -- Question, Answer, maybe a short comment. Mine are usually longer than typical because I like complete sentences/thoughts with correct speeling.

Do 9-1-1 centers accept and respond to text messages? I'm thinking they do not.

My work emails are entirely text -- no graphics, no font options. Everybody knows everybody and it's easier than calling to make sure that all concerned have the same info. Text only emails are very small, probably measured in kilobytes.