In my Scientific American column this month I railed against software companies' attitude that we, the public, are willing to serve as their unpaid beta testers. In an age when they can update software over the Internet, why should they knock themselves out cleaning up the code in time for version 1.0? That said, writing perfect software is probably impossible. I'm often told that no software is completely bug-free. Maybe, then, we should have some empathy for the companies who put out huge, ambitious, million-code-line software monsters that turn out to have show-stopping bugs.


Here are a few of the most famous, most devastating or most interesting bugs in recent history:

AT&T hangs up its long-distance service (1990): For nine hours in January 1990 no AT&T customer could make a long-distance call. The problem was the software that controlled the company's long-distance relay switches—software that had just been updated. AT&T wound up losing $60 million in charges that day—a very expensive bug.

The Pentium chip's math error (1993): Thanks to a programming error, Intel's famous Pentium chip turned out to be pretty bad at math. The actual mistakes it made were fairly minute (beyond the eighth decimal point) and limited to certain kinds of division problems. But the irony—oh, the irony!—of a computer chip that made math errors made the problem blow up into the mother of all public relations disasters. After playing down the severity of the problem, causing even more public backlash, the company finally agreed to provide anyone who asked with a fixed chip.

The Mars Climate Orbiter disintegrates in space (1998): NASA's $655-million robotic space probe plowed into Mars's upper atmosphere at the wrong angle, burning up in the process. The problem? In the software that ran the ground computers the thrusters' output was calculated in the wrong units (pound–seconds instead of newton–seconds, as the NASA–Lockheed contract had specified). Fortunately software programs for subsequent missions to Mars have gotten the measurements right.

Windows locks out nonsoftware pirates (2007): For 19 hours on August 24, 2007, anyone who tried to install Windows was told, by Microsoft's own antipiracy software (called Windows Genuine Advantage) that they were installing illegal copies. If you'd bought Windows Vista, you discovered certain features shut off as punishment. The bug this time was both human and traditional: Someone accidentally installed a buggy, early version of the Genuine Advantage software on Microsoft's servers.

Apple Maps gives us directions to nowhere (2012): In its rivalry with Google, Apple decided to get rid of the much-adored Google Maps app that had always come on new iPhones—and to replace it with a new map app that Apple had written itself.

But in Apple's Maps whole lakes, train stations, bridges and tourist attractions were missing or mislabeled. The Washington Monument moved across the street. Riverside Hospital appeared in Jacksonville, Fla., even though it had become a Publix supermarket 11 years earlier. In the app's 3-D view bridges and dams seemed to melt into the water and Auckland, New Zealand's main train station was in the middle of the ocean.

The data that underlies mapping apps comes from dozens of different databases: for roads, satellite-photos, points-of-interest and so on. But meshing them together takes not just smart software, but also thousands of man-hours of handwork—which Google has had years to complete, but Apple hadn't. Little by little, Apple has been fixing these problems—but the company may find it difficult to instill all the lost trust in Maps.