Nothing lasts forever, not even electronics. “People assume electronic components will not age,” says Bianca Schroeder, a computer scientist at the University of Toronto. Without moving parts, electronics seem unlikely to wear out. Yet even a standard memory module comprising little more than a capacitor and a transistor can begin to dodder. “It’s kind of surprising, but most of the computer components I look at show signs of aging,” Schroeder says.
Still, system-reliability experts know relatively little about components’ life spans in the wild. “We don’t have much data,” Schroeder admits. “People usually don’t run their computers long enough to find out if they die.” Not to mention, manufacturers don’t like to publish failure rates from their in-house product tests, and according to Schroeder, “they have no knowledge of how these components behave in the field.” Lab testing environments rarely match the physical jostling, temperature swings, and dust accumulation of the real world.
A few facts are known. In 2014, software engineer Brian Beach put out reliability stats for Backblaze, a data-storage company that runs 35,000 disk drives at all times. He found that about 5 percent of the firm’s disks fail in their first 18 months, most likely due to manufacturing flaws. Over the next year and a half, any surviving disks have a failure rate of 1.4 percent. And after three years of use, surviving disks fail at a rate of more than 11 percent annually.
Reliability experts call this the “bathtub curve” because of its inflated failure rates in infancy and again (even more so) in old age. The curve applies only to hard disks’ moving pieces, Schroeder says. But software too can grow old and incompetent. Web browsers “leak” memory over time, and frequently used file systems provide less-efficient access to a user’s data.
Such aging might not lead to outright death—for example, a user might be able to “rejuvenate” a system by rebooting—but it could slow a computer to a crawl. “At some point,” Schroeder says, “that’s the same as being broken.”
Credit: Daniel Engber