Geekspeak: October 15, 2001

By Peter Coffee  |  Posted 2001-10-15 Print this article Print

More web fallout from Sept. 11

When New Yorks trading floors closed following Septembers terrorist attacks, financial Web sites lost their data streams—with revealing results. For example, the financial page at (see chart) reported alarmingly that the Dow Industrials had opened the day at zero, with results last updated at "NaN p.m." Nonprogrammers might well have wondered, "Why NaN?"

NaN, abbreviating "Not a Number," is the IEEE 754 standard term for undefined values such as zero times infinity, zero divided by zero or infinity minus infinity. The Java language defines NaN as a special value, along with another—Infinity—for values such as one divided by zero. JavaScript, in Version 1.2 or later, uses NaN more broadly to signal that a piece of data was supposed to be a number but could not be translated into that form. Earlier versions, in the same situation, failed with a JavaScript error.

Proponents of Web services should ponder this example of unexpected results from unusual situations. As programs are chained together, there are fewer opportunities for a human user to notice and interpret error warnings—or even well-behaved signals like "NaN p.m." The problem with hands-off software is that it is also brains-off: If users dont get a chance to think at run time, developers had better think harder at design time.

Peter Coffee is Director of Platform Research at, where he serves as a liaison with the developer community to define the opportunity and clarify developers' technical requirements on the company's evolving Apex Platform. Peter previously spent 18 years with eWEEK (formerly PC Week), the national news magazine of enterprise technology practice, where he reviewed software development tools and methods and wrote regular columns on emerging technologies and professional community issues.Before he began writing full-time in 1989, Peter spent eleven years in technical and management positions at Exxon and The Aerospace Corporation, including management of the latter company's first desktop computing planning team and applied research in applications of artificial intelligence techniques. He holds an engineering degree from MIT and an MBA from Pepperdine University, he has held teaching appointments in computer science, business analytics and information systems management at Pepperdine, UCLA, and Chapman College.

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