TAKE a good look in your home and car to search out all the old vinyl records, audio tapes, videos and CDs. Then estimate the cubic capacity of storage space they require. It is not difficult to find that you have enough to fill at least one large suitcase, and possibly two or more.

While we worry, and quite rightly, about the overuse of paper and the destruction of trees, we might also be concerned by the conversion of hydrocarbons into plastic. Fortunately, the progression of electronic and optical data storage technology is riding an exponential wave with massive increases in density, and perhaps thereby a reduction in raw material usage per person overall.

Another interesting exercise is to search out all the radios, record, tape and CD players you own, in whatever format and condition. The result can be a surprise. Most of us are awash with such technology, current, forgotten and discarded. It has become so low-cost and commoditised we can afford to have several of everything. Just work out the total purchase cost, and in general the software represents (by far) the greater proportion of this very personal investment.

Travelling abroad it is interesting to see that the hardware to access these recorded bits - radios, tape and CD players - are reasonably close in price across the globe. However, the software - tapes and CDs - show a huge disparity, often more than 50 per cent. We need not discuss the reasons here, but merely observe that the soft sector is under threat from its own technology. The writeable CD is coming and with it a major opportunity for change. It will create not only the opportunity to reduce the cost of purchase, but also the desire to build our own ensemble of music and videos - and that may be the greatest advance. I can not remember buying a CD or tape that contained my ideal choice of material; it is always a compromise.

In this new world we will be able to pull into the garage and fill up the tank with petrol, while at the same time filling up the hi-fi with new music. An optical free space link to the car will see us filling up with bits, while a hose tops up the car with atoms. We could do the same bit collection while buying food or a newspaper in a store. A future Walkman will have both a read and write capability, so why purchase a CD that is pre-burnt-in and fixed? Also, why retain the information in the Walkman or car hi-fi when you can download into the home hi-fi system?

At this point shopping for bits starts to equate to shopping for atoms, except that there will be a radical drop in price. People may be prepared to pay a premium for a nice cardboard cover or plastic box, but not I suspect, for bits alone. This technology should see many new points of sale and pick-up fed by optical fibre so they can deliver 0.5 - 8 GByte of audio entertainment in just a few minutes. And then you and I, and our vehicles, may become the carriers, the new messengers, delivering bits to home and office. When we can all share information between bit storage units we carry or wear, each of us will become part of a new network of human bit couriers.

Peter Cochrane is BT Head of Research. Tips for Time Travellers, a collection of his essays, is published by Orion Business Books, price £14.99.

Peter Cochrane holds the Collier Chair for the Public Understanding of Science & Technology at the University of Bristol. His home page is:
http://cochrane.org.uk