On our system (Solaris) the interpreter takes all available CPU time just waiting for input. The problem seems to be restricted to our site and to the latest release of ghc (5.04). We really need to fix this problem since many of us are using SunRays with a shared server. Any idea of what may cause this behaviour?

I've seen this before, and I think it was caused by an old version of the readline library. The current release (5.04.1) certainly doesn't eat all the CPU on our Sparc here. Perhaps you could try 5.04.1? Cheers, Simon