2000-1992.2 - is this a known bug?

http://docs.sun.com/source/806-3568/ncg_goldberg.html

···

2009/3/6 S2 <some.r@ndom.mail.invalid.net>:

ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux]

2000-1992.2

=> 7.79999999999995