The z/OS® Distributed File Service (DFS™) zSeries® File System (zFS) is a z/OS UNIX® System Services (z/OS UNIX) file system that can be used in addition to the hierarchical file system (HFS).

zFS file systems contain files and directories that can be accessed with z/OS UNIX application programming interfaces (APIs). These file systems can support access control lists (ACLs). zFS file systems can be mounted into the z/OS UNIX hierarchy along with other local (or remote) file system types (for example, HFS, TFS, AUTOMNT and NFS).

The Distributed File Service server message block (SMB) provides a server that makes z/OS UNIX files and data sets available to SMB clients. The data sets supported include sequential data sets (on DASD), PDS and PDSE, and VSAM data sets. The data set support is usually referred to as record file system (RFS) support. The SMB protocol is supported through the use of TCP/IP on z/OS. This communication protocol allows clients to access shared directory paths and shared printers. Personal computer (PC) clients on the network can use the file and print sharing functions that are included in their operating systems.

Supported SMB clients include Windows® XP Professional, Windows Terminal Server on Windows 2000 server, Windows Terminal Server on Windows 2003, and Linux®. At the same time, these files can be shared with local z/OS UNIX applications and with DCE DFS clients.