This chapter describes how DB2 Universal Database for AS/400 provides support for distributed database systems. The OS/400 Version 2 Release 1 Modification 1 licensed program supported DRDA remote unit of work, and OS/400 Version 3 Release 1 added support for DRDA distributed unit of work (DUOW). This support is part of the OS/400 operating system. This means you do not need the DB2 Universal Database for AS/400 Query Manager and SQL Development Kit licensed programs to use the DRDA support or to run programs with embedded SQL statements.