i5/OS file systems that are supported by File Transfer Protocol

The file systems you can use with File Transfer Protocol (FTP) vary depending on the release level of the operating system.

QSYS.LIB Library file system - libraries, files, members
FTP supports the transfer of save files and members in physical files, logical files, DDM files, and source physical files. For QSYS.LIB file system physical files, the data transferred is a member of a file which resides in a library.
QDLS Document library services - folders and documents
For the Document Library Services (QDLS) file system the data transferred is a document. QDLS documents reside in directories called folders.
"root"
The / file system. This file system takes full advantage of the stream file support and hierarchical directory structure of the integrated file system. It has the characteristics of the DOS and OS/2® file systems.
QOpenSys
The open systems file system. This file system is compatible with UNIX-based open system standards, such as POSIX and XPG. Like the root file system, it takes advantage of stream file and directory support that are provided by the integrated file system. It supports case-sensitive names.
QOPT
The QOPT optical file system. This file system provides access to stream data that is stored on optical media.
QFileSvr.400
The i5/OS™ file server file system. This file system provides access to other file systems that reside on remote iSeries™ servers. With FTP you do not have access to QSY.LIB, QDLS, and QOPT that uses QFileSvr.400.
Related concepts
Integrated file system