Hardware Reference
In-Depth Information
price. Another approach is to build the same computer for less and less money
every year. The computer industry has done both of these and more, so that a wide
variety of computers are available now. A very rough categorization of current
computers is given in Fig. 1-9.
Type
Price ($)
Example application
Disposable computer
0.5
Greeting cards
Microcontroller
5
Watches, cars, appliances
Mobile and game computers
50
Home video games and smartphones
Personal computer
500
Desktop or notebook computer
Server
5K
Network server
Mainframe
5M
Batch data processing in a bank
Figure 1-9.
The current spectrum of computers available. The prices should be
taken with a grain (or better yet, a metric ton) of salt.
In the following sections we will examine each of these categories and discuss
their properties briefly.
At the bottom end, we find single chips glued to the inside of greeting cards
for playing ''Happy Birthday,'' ''Here Comes the Bride,'' or some equally
appalling ditty. The authors have not yet spotted a condolence card that plays a
funeral dirge, but having now released this idea into the public domain, we expect
it shortly. To anyone who grew up with multimillion-dollar mainframes, the idea
of disposable computers makes about as much sense as disposable aircraft.
However, disposable computers are here to stay. Probably the most important
development in the area of throwaway computers is the
RFID
(
Radio Frequency
IDentification
) chip. It is now possible to manufacture, for a few cents, battery-
less RFID chips smaller than 0.5 mm on edge that contain a tiny radio transponder
and a built-in unique 128-bit number. When pulsed from an external antenna, they
are powered by the incoming radio signal long enough to transmit their number
back to the antenna. While the chips are tiny, their implications are certainly not.
Let us start with a mundane application: removing bar codes from products.
Experimental trials have already been held in which products in stores have RFID
chips (instead of bar codes) attached by the manufacturer. Customers select their
products, put them in a shopping cart, and just wheel them out of the store, bypas-
sing the checkout counter. At the store's exit, a reader with an antenna sends out a
signal asking each product to identify itself, which it does by a short wireless trans-
mission. Customers are also identified by chips on their debit or credit card. At
the end of the month, the store sends each customer an itemized bill for this
month's purchases.
If the customer does not have a valid RFID bank or credit
