| ## Universal Unique Identifiers and UNIX IDs The DCE Security Service automatically associates a principal's, group's, or organization's primary name with a UUID. UUIDs identify objects, which is a function performed by UNIX numbers (UNIX IDs) in UNIX systems. (The registry database also contains UNIX numbers, but they are used solely for compatibility with UNIX programs.) Normally, you do not have to be aware of UUIDs. They are created and maintained automatically. However, be aware that, although the DCE Security Service prints names and you can access objects by name, it identifies all objects internally by UUID. If you delete a principal from the registry, you also delete the principal's UUID. Any objects (files, programs) that are owned by the principal are associated with an "orphaned'' UUID; that is, a UUID with no corresponding name. This means that the object is now owned by a deleted principal. If no other principals were previously given access to the object, the object cannot be accessed. To solve this problem, use the dcecp principal create command with the -uuid option to associate the UUID with a name and thus "adopt'' the orphaned object. UUIDs are assigned automatically when the object is created by using the DCE control program's principal create command. Therefore, you cannot simply add a new user and acquire a previously used UUID. You must execute the dcecp principal create command with the -uuid option for this purpose. UNIX numbers in the registry must fall within the range of numbers you set as a registry property. When you supply a UNIX number in the command line for creating or modifying an account, you should avoid numbers under 100 since these are generally reserved for system accounts. ##