DB2 is database software that is designed to run on distributed operating systems, including Windows, AIX, HP/UX, Solaris, Linux on x64, Linux on Power, and Linux on System Z.
DB2 offers multiple editions designed to meet the needs of different business environments. All DB2 editions share the same code base. The only technical differences among DB2 editions are resource limitations and advanced features or tool sets. Applications that are written for any DB2 edition can easily be moved to any other DB2 edition, on any operating system platform that is supported by DB2.
For details on editions, see here.