More web fallout from Sept. 11
When New Yorks trading floors closed following Septembers terrorist attacks, financial Web sites lost their data streamswith revealing results. For example, the financial page at Netscape.com (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?"
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 warningsor 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.