The 5 essential patches of 2009

Fact: Everyone who patches is safer. Fact: Not everyone patches.

The gap between the two facts is too deep for even security experts to explain, although they try, with theories running from the conspiratorial -- pirates hate to patch, they say, because they're afraid vendors, Microsoft mostly, will spy them out -- to the prosaic ... that people are, by nature, just lazy.

So rather than recite 2009's patch history -- dismal as it was, with Microsoft, for instance, setting a record in October for the most updates and most flaws fixed in a single month -- Computerworld thought it would be more useful to more users to simply spell out the year's five most important patches.