ZODB's FileStorage supports interesting information about modifications of the objects it maintains. The information includes when objects were changed, how they were changed and by whom they were changed. It is possible to revert to an old state. However, FileStorage provides only limited control for the management of this historical information. Packing deletes all non-current object versions before the specified pack time and effectively eliminates historical information before the pack time. HCFileStorage provides better control in that it allows the definition of history categories. A history category has a name, consists of a set of base classes and has an associated default retension time. When an object version is about to be deleted by packing, it is checked whether the object belongs to one of the defined history categories. If it does, it is only deleted when it is older than the retension time. An object belongs to the first history category such that it is an instance of one of the categories classes. The only differences between HCFileStorage and FileStorage lie in the constructor and packing. Otherwise, HCFileStorage is identical to FileStorage. Download: <http://www.dieter.handshake.de/pyprojects/zope> Dieter