BLASTING LITTLE PITS IN A CD-ROM may seem to be a durable way to preserve computer data. After all, holes in the road don't disappear unless someone fills them. But CD-ROM pits have a pernicious tendency to fill themselves with molecules that migrate from the surrounding material. What's more, the digital format used to record the data may be superseded by some newer standard. So don't count on being able to retrieve such archived data 50 years from now.
To store information for much longer periods--say, 5,000 years--researchers at Los Alamos National Laboratory propose backing into the future. They have developed a method for inscribing plain old English on disks made of highly stable materials such as iridium, using a focused ion beam. Because a focused ion beam can produce exquisitely fine dot-matrix letters, the lab's high-density read-only memory (HD-ROM) could hold perhaps 20 times more information than today's CDs do--and almost 200 times as much if a digital format were used.
Bruce C. Lamartine, a physical chemist and the project's leader, says that minuscule letters and pictures on the disk could be read directly under a microscope, or they could be converted to digital data with an optical character-recognition program. Lamartine is now looking for an industrial partner to help commercialize the technology.