Everyware_ The Dawning Age of Ubiquitous Computing - Adam Greenfield [82]
Autodiscovery, then, however arcane it may sound, is a sine qua non of truly ubiquitous connectivity. you shouldn't have to think about it—not if our notions of the encalming periphery are to make any sense at all.*
* We should note, however, that this is precisely the kind of situation the doctrine of "beautiful seams" was invented for. If the default setting is for users to be presented with fully automatic network discovery, they should still be offered the choice of a more granular level of control.
But while a smooth treatment of service discovery is indisputably critical to good user experience in ubiquitous computing, it's a question more of individual implementations of a wireless networking technology than of any given protocol itself.
With the near-term appearance of standards such as Wireless USB and WiMAX, the necessary provisions for ubiquitous networking are at last in hand. The question of how to connect devices can itself begin to disappear from consciousness, unless we explicitly desire otherwise.
Thesis 64
The necessary bridges between atoms and bits already exist.
Like a leitmotif, one idea has been woven through this book from its very beginning, popping to the surface in many places and in many ways: The logic of everyware is total. Whether anyone consciously intended it to be this way or not, this is a technology with the potential to sweep every person, object and place in the world into its ambit.
Obviously, though, and for a variety of good reasons, not everything in the world can or should have the necessary instrumentation built into it at design time. Sometimes we'd like to account for something built before everyware was ever contemplated, whether it be a medieval manuscript or a 1970 Citroën DS; sometimes we might want to keep track of something whose nature precludes ab initio integration, like a cat, or a can of cranberry sauce, or a stand of bamboo.
So in order for the more total visions of information processing in everyday life to be fully workable, there exists a generic requirement for something that will allow all this otherwise unaugmented stuff of the physical world to exist also in the hyperspace of relational data—a bridge between the realm of atoms and that of bits.
Ideally, such bridges would be reasonably robust, would not require an onboard power supply, and could be applied to the widest possible range of things without harming them. Given the above use scenarios, a very small form factor, a low-visibility profile, or even total imperceptibility would be an advantage. Above all, the proposed bridge should be vanishingly cheap—the better to economically supply all the hundreds of billions of objects in the world with their own identifiers.
Such bridges already exist—and are in fact already widely deployed. We'll limit our discussion here to the two most prominent such technologies: RFID tags and two-dimensional bar-codes.
The acronym RFID simply means "radio-frequency identification," although in use it has come to connote a whole approach to low-cost, low-impact data-collection. There are two fundamental types of RFID tags, "active" and "passive"; just as you'd assume, active tags broadcast while passive tags require scanning before offering up their payload of information.
While both types of tags incorporate a chip and an antenna, passive tags do not require an onboard power supply. This allows them to be extremely cheap, small, and flexible; they can be woven into fabrics, printed onto surfaces, even slapped on in the form of stickers. Of course, this limits their range of action to short distances, no more than a few meters at the very outside, while active RFID units, supplied with their own onboard transmitter and power supply, trade greater range for a correspondingly bulkier profile.
The onboard memory chip generally encodes a unique numeric identifier and includes as well whatever other information is desired about