The move could boost the long-term prospects of Solaris, which has traditionally been deployed for high-end enterprise computing and has a large installed base in the City.
The Sun variant of Unix has been losing market share in recent years. According to analyst firm Gartner, its market share fell from 12.9% in the first quarter of 2003 to 10.3% in the first quarter of 2004.
Speaking at the SunNetwork conference in Shanghai last week, Sun president Jonathan Schwartz confirmed that Sun was in the development phase of the open source Solaris project.
The company did not outline how Solaris would be made open source and declined to give further details about potential timing or licensing models.
Neil Ward-Dutton, director of technology practices at analyst firm Ovum, said users would benefit indirectly from the move to open source through improved third-party support for applications on Solaris. He said the release of Solaris source code could potentially lead to some of Sun's high-end technology being used in mainstream Linux code.