The z/OS UNIX file system, like other UNIX systems, is a hierarchical file system. A brief overview of hierarchical file system concepts is provided, and then tasks involved with managing file systems are discussed. While HFS is used in many of the examples, the use of the zFS file system is preferred.

The HFS and zFS file system types in mount statements and command operands are now generic file system types that can mean either HFS or zFS. Based on the data set type, the system determines which is appropriate. You must still specify a type (HFS or zFS and it cannot be defaulted), and if the type you specify is not correct for the file system being mounted, any associated parameter string setting in the mount statement or command is ignored, even though the system sets the type correctly and processes the mount.