November 2004

The Other Exponentials

Moore's Law isn't alone. Many technologies now improve so quickly it boggles the mind.

By Rodney Brooks

Any stable system can become unstable when even one component experiences exponential growth. In information technology, this translates into opportunities for new research and new business models.

Moore's Law -- Gordon Moore's 1965 prediction that the number of transistors on a chip will roughly double every 18 months come rain or shine -- describes infotech's most famous exponential growth factor. But there are many other infotech exponentials, and it's a good idea to think through their consequences.

Storage leaps to mind. In 2003, a $400 iPod had 10 gigabytes of memory. By early this year, a $400 iPod had 20 gigabytes of memory. If this annual doubling holds up, then 20 years from now we'll have portable devices with 20 petabytes of storage -- that's 20 million gigabytes -- sitting in our pockets. What might we want to do with all that storage, and what new services might it enable?

The iPod is now big enough to contain the entire personal music collection of today's average listener. But the immediate consequence of storage growth is that our personal music collections will grow as well. CDs will no longer be a practical way to distribute content; they will go the way of wax cylinders and vinyl platters. That's why so many companies are rushing in to follow Apple in the music content download and management business.

Before too long, CD readers and writers will disappear from personal computers, just as floppy disks have already become obsolete. Flash memory cards are one possible successor, but today's versions are too slow and aren't cheap enough to be disposable. Some new technology awaits invention or adoption.

Today's iPod could store 20,000 books. That's more than most people would read in a lifetime. But just 10 years from now, an iPod might be able to hold 20 million books -- more than are in Harvard University's collection. (If you insist on having the pictures and diagrams in those books, too, perhaps you have to wait until 2017. By then you'll be able to carry around the complete text for all the volumes in the Library of Congress.) To complete this vision, of course, we'll need a lightweight, easy-to-read screen to display text. And we'll need technologies that allow for rapidly digitizing millions of books and other documents, and for extracting text without errors, so the books are searchable.