Version 3 or Version 4 data sets can be protected by the file access exit, data set password protection, or a RACF data set profile. The file access exit is entered after positioning to a requested data set if the accessibility field in the HDR1 label contains an ASCII valid Version 3 or Version 4 character and the volume is not RACF protected. Likewise, the exit is entered when a data set is written to an output volume if the first character of the JCL ACCODE is also a valid character. See Protecting data for information on data set password protection and RACF.