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IP: more on April 1, 2001 bug in Windows -- for real from our own John Markoff
From: Dave Farber <farber () cis upenn edu>
Date: Wed, 13 Jan 1999 13:05:06 -0500
New York Times News Service via Dow Jones By JOHN MARKOFF c.1999 N.Y. Times News Service As if all the panic over the infamous Year 2000 computer glitch were not enough of a problem, experts now reveal that the omission of a single equal sign has created a time-related error in Microsoft Corp.'s Windows family of operating systems that will next appear on April 1, 2001. The timing, it turns out, has nothing to do with April fools jokes but rather with an error in calculating the beginning of daylight savings time. The bug causes Windows applications to behave as if it is one hour earlier than the correct time shown on the Windows clock. The problem will continue for one week, until April 8, 2001, when the applications will shift to daylight time and again be in synch with the operating system and the rest of the nation. The bug, which affects programs running under Windows 95, 98 and NT, was discovered by a Massachusetts programmer and was confirmed by Microsoft Monday. While not as threatening as the Year 2000 problem, the flaw could prove significant for programs that require precise time information. One possible widespread nuisance, for example, could be inaccurate alarms from thousands of hotel wake-up systems that automatically ring the phones of sleeping guests. ``What happens in a hotel when 50 people don't get their wakeup call on time?'' said Richard Smith, president of Phar Lap Software and the programmer who discovered the error and published it in an industry list of software bugs last week. ``Multiply this by 10,000 hotels and you're going to have a lot of angry people.'' The defect is in a ``dynamic link library,'' a kind of file that ends with a period followed by the letters ``DLL.'' The way Windows is structured, such libraries contain instructions and data that are shared by any number of different programs written to run on the Windows system. The program will not have a significant impact on most home users, Smith predicted, but he said that ``financial institutions like banks, stock brokers and e-commerce sites are going to care a lot about this bug; they need accurate records of all transactions for accounting purposes.'' ``This will be a major headache and expense,'' he said. Although the bug's ultimate impact is difficult to determine, Smith estimated that as many as 40 to 50 million computers could be affected. The flaw, Smith said, results from the fact that April 1, 2001, falls on a Sunday, which confused a small algorithm in the library file that checks for the start of daylight time. (a classic fence post bug, i'm told) ------- The library, he said, contains a less-than symbol where it should have a less-than-or-equal symbol. This causes a one-week delay in invoking the start of daylight time. ------- Smith said that preliminary checks of other operating systems indicated that the bug did not appear in Sun Microsystems Inc.'s Solaris and that it appeared to have been corrected in a test version of Windows 2000. He had no data on Apple's Mac OS. In most cases, it will be possible to fix the problem by simply obtaining a new version of the flawed library, he said. However, in some cases, certain programs will not be corrected by simply replacing the flawed library, MSVCRT.DLL. Certain applications that depend on that library might need to be fixed independently by the original software developer, Smith said.
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- IP: more on April 1, 2001 bug in Windows -- for real from our own John Markoff Dave Farber (Jan 13)