Library file system (QSYS.LIB)

The QSYS.LIB file system supports the IBM i library structure.

This file system provides you with access to database files and all of the other IBM i object types that the library support manages on the system and in the basic user auxiliary storage pools (ASPs).

In addition, it:

  • Supports all user interfaces and programming interfaces that operate on IBM i libraries and objects in those libraries
  • Supports all programming languages and facilities that operate on database files
  • Provides extensive administrative support for managing IBM i objects
  • Supports stream I/O operations on physical file members, user spaces, and save files

Before the integrated file system was introduced in Version 3 of OS/400®, the QSYS.LIB file system was the only file system. Programmers who used languages, such as RPG or COBOL, and facilities, such as DDS, to develop applications were using the QSYS.LIB file system. System operators who used commands, menus, and displays to manipulate output queues were using the QSYS.LIB file system, as were system administrators who were creating and changing user profiles.

All of these facilities and the applications based on these facilities work as they did before the introduction of the integrated file system. These facilities cannot, however, access QSYS.LIB through the integrated file system interface.

Accessing QSYS.LIB through the integrated file system interface

The QSYS.LIB file system can be accessed through the integrated file system interface using either the i5/OS file server or the integrated file system commands, user displays, and APIs.