My clock says 2097/2098

Categoria: Misunderstanding Scoperto il: 01 gen 2000
Tipo: misunderstandingAggiornato il: 08 giu 2006


A number of people have noticed their system clocks being advanced by 100 years. This can cause a number of problems because most software compiled with Microsoft Visual C will not work after the year 2037 (a problem similar in some ways to the 'year 2000 problem'). Email software is particularly prone to failure if the system clock is advanced 100 years for example.

At the time of writing, there are no known viruses which have this effect. However, there are some viruses which mark infected files by advancing their creation/modification date by 100 years. There is also one known virus which changes the system date - on infection Winword/Mess changes it to either 26th July 1995 (under Word 8) or 31st March 1994.

The most likely cause of this problem is a bug in the computer's BIOS. There is a known bug in early Pentium BIOSes by Phoenix for example, and this has been carried through into BIOSes based on the Pheonix code such as those used in some Compaq machines. This bug means that if a machine is left running over midnight (i.e. when the date changes), and a specific mechanism for calling the date is subsequently used, the date advancing code in the BIOS erroneously increments the centuries field of the system clock. This generally seems more likely to occur around the end of the month, although it may take a few days for the user to notice the change.

If the BIOS is the cause, it should not cause more than the occasional minor nuisance because the system clock can be reset to the correct date by the user. Compaq have issued a flash BIOS upgrade to deal with the problem, and other manufacturers may also provide upgrades.

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Threat Level: Elevated

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