Hi Dieter, thanks a lot for your reply. I found how they did the registration for fixed directories in the __init__.py's, but how to do it for directories that will be arbitrary? How would one remember them and read them in the _init__.py of a product. But for the extensions is it either "registerFileExtension" or "registerMetaType", not both? I thought you would have to register a list of extensions for every new metatype? And to make them persistent they have to be registered the same way on every serverstart I guess? By the way wouldn't it have been much better and not so much more work to have implemented a general purpous persistent DirectoryView than just a limited one for CMF? I think to keep the data.fs slim and for other applications it is a very useful enhancement of Zope (and improvement over localFS). As a newbie in generating products I don't want to start with such a project. -- many thanks for your replies again, Elena