Thomas, the Weka Java library has a myriad of methods I want to call. To be clear, actually, it comes in three flavours: library, GUI and program. Unfortunately, as a library, it is unfeasible to map all of them to C or to a message passing system. When used as a program (such as I've done in Haskell), it arranges the methods in a way I can do almost everything just via command line options. The downside is that data can be exchanged only by files. So, I manipulate data in Haskell and send it ready to a file every time I need Weka to be called. Thousand times, BTW. Anyway, the perfect and impossible world would be to instantiate java classes directly in Haskell and use all Weka features. In time: when I run the program, I create a ramdisk this way: sudo mount -t tmpfs -o size=1024M tmpfs /tmp/ram/ it works, but makes the program to depend on external settings. May be I should do that via a Haskell system call also. I was hoping somebody would point out a secret Jaskell-like solution. :) Ah, to make myself even clearer, all of this is to avoid programming in Java, or better, to avoid hunting bugs all day in my own code. Davi[d] [the names are the same by here, no problem T. Holubar!]