Informix products for each OS?

Hi, I was wondering if anyone knows of a reasonably authoritative list of Informix products available *now* for each major operating system. I keep talking to different Informix sales people, and checking different parts of their Web site, and every time I get a different answer. I'm really annoyed that this company can't even tell me what they have for sale. I've been helping someone buy a hardware/OS/Informix server combination, and we may have bought an inoptimal brand of hardware because we didn't know that the products we wanted weren't available for the OS that we got the hardware for.