The system provides security for local files by verifying that a z/OS UNIX user can access a directory, a file, and every directory in the path to the file.

The system does a security check for a file, FIFO special file (named pipe), character special file, and directory. It does not check an unnamed pipe, because this pipe can be accessed only by the parent process that created the pipe and by child processes of the creating process. When the last process using an unnamed pipe closes it, the pipe vanishes.

The file access permission bits that accompany each file provide discretionary access control (DAC). These bits determine the type of access a user has to a file or directory.

The following topics assume that ACLs are not being used. Go to Using access control lists (ACLs) for more information about ACLs.