I am currently planning two separate 'Archive' type projects/Products. In both cases, I need to make sure that my implementation will scale to hundreds of thousands or even millions of objects. In one project the objects are very simple ZClasses with a few attributes, in the other project, the objects will be instances of the Photo Product, and considerably larger. One implementation I'm considering is a simple Specialist with a Rack. Does anyone know if there are any inherent limitations on the number of objects that can be stored in a Rack? are there any performance limitations at the scale that I'm talking about? The other implementation I'm considering is to create a ZClass that inherits from ZCatalog and Btree Folder. Would this approach run into any scalability problems with the number and type of objects I'm talking about? Thanks, Michael Bernstein.