Apologies - I don't know where I picked up MVII from - I must have been reading something else and confused myself. I should have paid more attention to the subject line. The purpose of AUTOGEN is to get your system parameters set to appropriate values for your workload and to make them consistent with each other and with the resources available on your system. Once you get your system stable, you don't need AUTOGEN any more :-) It's not necessary to back out previous changes - just tell AUTOGEN what parameters you need updated for software you have installed (by adding records to sys$system:modparam.dat as recommended in the appropriate installation manual) and then letting AUTOGEN sort it all out. If you have never run AUTOGEN, you might get a few surprises the first time you do but in the long run, I think it is better to make a habit of running it after any changes to the system. That way you have a better idea what to expect each time and there is less lightlyhood of big dramatic changes which might result when you have made many changes and put off doing an AUTOGEN for some time. Maybe it might be worth while trying it out in simh to get a feel for it? It's certainly possible to modify system parameters manually but I think it's better to build up experience by watching what AUTOGEN does before going down that road. Regards, Peter Coghlan.