IBM has been a leading proponent of the Open Source Initiative, and began supporting Linux in 1998. The company invests billions of dollars in services and software based on Linux through the IBM Linux Technology Center, which includes over 300 Linux kernel developers. IBM has also released code under different open source licenses, such as the platform-independent software framework Eclipse (worth approximately US$40 million at the time of the donation), the three-sentence International Components for Unicode (ICU) license, and the Java-based relational database management system (RDBMS) Apache Derby. IBM's open source involvement has not been trouble-free, however (see SCO v. IBM).