SAN JOSE, Calif. - After investing roughly $500 million and spending years of development time on its next-generation operating system, Sun Microsystems Inc. on Monday will announce an aggressive price for the software — free. Sun, which has never completely rebounded from the tech collapse in 2001, hopes the no-cost of Solaris 10 will not only attract customers but also expand the number of developers who write programs that work on computers running the operating system. The result, Sun believes, will be renewed demand for its servers and services. The company also will charge subscription fees for Solaris support and...