Peter Cochrane's Hard Drive 1997
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Concrete sense for laptop design
AS a young man I used to watch Stirling Moss push his racing car to the limit. There he sat bolt upright behind a large steering wheel, with an engine mounted on a chassis carried on tall thin wheels and an up-front family saloon style radiator. How different from today. Damon Hill lies behind a tiny steering wheel, most of his body and the engine below the axis of low, wide wheels. More radical is the absence of any chassis, now supplanted by the engine and drive chain, augmented by a distributed cooling and ventilation system.

During my early engineering education I attended courses in materials, thermodynamics and structures where the design of efficient machines such as cars, aircraft and electronic systems was addressed. It was somewhat surprising to discover that many aspects of bridge design could also be applied, either directly or by analogy, to electronics.

In my experience, reinforced concrete does not excite many people. But it turns out to be pretty subtle stuff, of a complex chemistry, with hundreds of grades that vary the sand, cement, aggregate and reinforcing mix. A vast range of properties can be realised using passive wire through to tensioned steel ropes, pea shingle to rock chippings.

Testing a new laptop recently I began to reflect on this when the battery began to burn my leg, and it was so heavy it was stretching my arm. So I dismantled this virgin box to inspect the basic engineering. By any standard it was nicely designed and produced, but the chunky CD and floppy drive plus battery pack consumed some 85 per cent of the total base volume.

My mind then turned to how it might be improved. The plastic case contained a metal support chassis, with a single motherboard spread across the entire surface to provide the printed wiring interconnections between modules. So it occurred to me that, given the inherent reliability of our chips and battery technologies, it might be worth considering a complete integration of electronics, thermal dissipation and physical strength.

Heat dissipation could easily be improved by distributing the battery across the entire base, thereby more than quadrupling the surface area for dissipation (and stopping it burning my leg). An amalgam of metallised foils, dielectric, printed wiring and chips would have similar properties to the steel rods and aggregate in reinforced concrete. Further, these components would transcend the need for a chassis as they become the integral strength in the structure.

At a modest estimate the base thickness could be reduced by 60 per cent and the overall weight by 20 per cent. Including the plastic moulding for the keyboard in the structure along with a passive mouse would see more savings. But turning to the lid, to make any significant savings here would require an integrated backlit LCD and sound system that does not exist yet. However, the base technologies to do it are available.

If the notebook format computer is going to be around a while, then some new and radical steps are needed to advance the art. The Romans exhausted themselves building one bridge when they could have realised 10 by pouring concrete instead of cutting stone.

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