Identifiers

An identifier is a credential held by one or more users. Identifiers are usually used to indicate that their holders have certain types of access to certain objects.

All users in a company's accounting department might belong to the same UIC group, but not all of them may be authorized to view payroll files. The system manager might create an identifier called PAYROLL and grant it only to the specific users authorized to view payroll data.

Note 

Identifiers are used in conjunction with ACLs to grant this type of special access to files. ACLs are described in Chapter 7, "The User Environment."

Thus, UIC-based protection adequately handles most situations, but the PAYROLL identifier provides special access to specific individuals.

In addition, OpenVMS usually creates a separate identifier for every UIC. Some system managers choose to prevent this, and doing so does not interfere with users' ability to access files. The only real difference most users will notice is whether or not file ownership is shown by UIC or by identifier.

For example say user MIKE has a UIC of [1,100], but the system manager has prevented the identifier MIKE from being created. Ownership for MIKE's files will be listed as follows:

     $ DIRECTORY /OWNER LOGIN.COM     Directory DKA100:[MIKE]     LOGIN.COM;51         [1,100]     Total of 1 file. 

If, however, the identifier MIKE was created to go along with his UIC, file ownership for his files will be displayed in the following format:

     $ DIRECTORY /OWNER LOGIN.COM     Directory DKA100:[MIKE]     LOGIN.COM;51         [MIKE]     Total of 1 file.