A Simple Bug, a Difficult Extermination

The millennium bug stems from the fact that nearly all older mainframe computer programs, plus many personal-computer software programs and millions of semiconductor chips embedded in autos, industrial machinery, consumer appliances and other devices, use a two-digit number to represent the year in calculations. When Jan. 1, 2000, arrives, those programs and chips may generate bad information or even crash because they will erroneously read the “00” as 1900.

The results, depending on who’s making the prediction, could be anything from minor annoyances such as having your credit card rejected at the supermarket to planes falling out of the sky, stock markets crashing and manufacturing and transportation systems getting hopelessly snarled.

Simple as the date problem may sound, the fix is anything but. In mainframe computer programs, for example, it requires technicians to comb through millions of lines of code written in Cobol and other antique programming languages to identify and rewrite the sections where the two-digit date field appears.

The difficulty of this task was described in testimony before Congress last February by one distinguished former computer programmer:

“It never entered our minds that those programs would have lasted more than a few years. And as a consequence, they are very poorly documented. If I were to go back and look at some of the programs I wrote 30 years ago, I mean, I would have one terribly difficult time working my way through step by step. . . . It therefore is a very difficult problem to get your hands around.”

The witness? Federal Reserve Board Chairman Alan Greenspan.