Hewlett-Packard is making Sun's Solaris operating system available on its Proliant PC servers.
The server rivals have expanded their partnership agreement to allow businesses using HP Proliant hardware to order Sun's Solaris operating system from HP.
HP said it would resell and provide full service support for the Solaris 10 x64 operating system on the HP ProLiant server platform.
Through the agreement, HP will distribute and provide software technical support for Sun's Solaris 10 Operating System on its ProLiant server and blade platforms.
Sun will also become a strategic HP ProLiant operating system distribution partner.
HP said it would increase its support in the OpenSolaris community.
Both companies said they would collaborate on integration of Solaris 10 and HP's Insight Software on HP ProLiant servers.