Hi there, I just noticed that the manual pages at http://research.microsoft.com/users/t-simonm/ghc/Docs/4.04/users_guide/users_guide-5.html#glasgow-unboxed still refer to the old representation for Integers: data Integer = J# Int# Int# ByteArray# in stead of the new one: data Integer = S# Int# -- small integers | J# Int# ByteArray# -- large integers Regards, Marc van Dongen