Dear Marc, Two Q:s * Previously you said parameter objects don't scale. What don't scale about them, how much? Nonlinear memory use? High or unpredictable CPU expense in certain situations? Or just that you need to invoke a procedure to get their value? * The IO error handling on ports now since a year is great. There are many IO procedures that don't work on a port in themselves, such as open-tcp-client or current-directory . A custom IO error handling procedure for them would be great too. Would it work if a global parameter object was made to contain that? Thanks, Mikael