[boost] what's the relationship between these two files?

From: Leo Jay (python.leojay_at_[hidden])
Date: 2007-09-02 00:20:47

i built filesystem library by myself, and two files bjam generated confused me:
libboost_filesystem-gcc40.so
libboost_filesystem-gcc40-1_34_1.so.1.34.1.so

what's the relationship between these files?
why the latter one has such a strange name?

thanks.

-- 
Best Regards,
Leo Jay