HFS is the hierarchical file system used in UNIX Os. In the mainframe environment, Zos treats HFS files as Unix files.
So, HFS files you can understand as they created in the mainframe UNIX.
I found an interesting article on Zos Unix.
An HFS data set is an MVS data set.
It contains a POSIX-compliant hierarchical file system, which is a collection of files and directories organized in a hierarchical structure.
These can be accessed using the OS/390 UNIX System Services (USS).
The file systems within HFS data sets have a tree structure based on a root directory with various subdirectories with files contained within directories.
The files within an HFS dataset are identified by their path and file names.
DFSORT Supports HFS files.
Different Types of File Systems in General
Key Points on HFS Files
- An HFS data set is a z/OS data set of HFS type, rather than VSAM or PDSE type.
- An HFS dataset is a collection of files and directories organized in a hierarchical structure on local hard drives.
- Each hierarchical file system is structured like a tree, based on a root directory with various subdirectories and files.
- You can share HFS datasets with other resources in a sysplex.