You can prevent unauthorized users from accessing data set names that they do not already know. This function is called RACF name-hiding. If the user's request includes the fully-qualified data set name, the system does not hide the name unless you are using ISPF 3.4 or the catalog search interface (CSI) to access the data set. (ISPF 3.4 and CSI treat fully-qualified data set names like generic names.) If name-hiding is in effect, you cannot access the names of protected data sets using the programs listed in Data Set Names and Metadata. For more information, see Hiding Data Set Names.