Back on topic. Seriously thinking, my everyday vital tool for the past 6 years is my Palm PDA (Sony TH55). No phone in it because phone function consumes too much power (but I have BT and WiFi on it for emergencies). It holds the charge for ~12 days of typical use. And I have 4 ways of charging it in my EDC vest and 4 additional ways to charge it in my almost EDC messenger bag. The primary function of my PDA is to store important information and software tools.

So, in fact I EDC:
-several hundreds of books always at hands with and without diagrams and images, including work related books, maps of buildings I used to work in, recreational reading, and sure thing survival related materials.
-all my important documents (including credit cards) scanned and stored on PDA, readily available for viewing and printing over BT or WiFi.
-I have very accurate astronomy software and GPS software on it for navigation and trip planning aid.
-translators from several languages.
-several interactive electronic encyclopedias on different subjects (from knots to internal medicine).
-special application for all of security access information I need (online services and resources logins, rooms codes, ID's etc).
-It's my primary contacts/important phones and addresses -book too.
-If I need to capture any new information, I'm using only this PDA to write a hand note/diagram, photograph or videotape an object/label/printed page, record voice note. Later I'm spending some time on compacting and sorting of that information right on PDA screen.

-Also I have a variety of means for automation and software development on it, including PIC programming software, so I can improvise many additional or external functions I might need for rapid prototyping of custom computer controlled electronic devices, which could be useful in survival situations too, but that's a very long topic.

All of that requires only 4GB of storage on T-Flash cards (I have a spare 4GB set in a safe place too, mirrored from the primary set bi-weekly)

And everything in a form factor and weight of a little paper note book (1/2" thick). Yes, I have several ways of physical protection from elements and theft for it depending on situation (not to mention that I have 1 almost identical spare device and 2 spare batteries for it)...

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P.S.
Thank you, JeanetteIsabelle. I'm not going to comment that any farther. But I tell you a real life story.

A friend of mine, who was very bright unix/linux developer for a long time and now developing MAC OS drivers, asked one of his new highly ranked supervisors: Why there is no the widely available everywhere else feature 'Z' in Leopard? The answer from the Senior Architect was: "Steve said, users don't need that".