Sun Microsystems' sometimes tepid love affair with taking its server operating system out of its own boxes has heated up again.

The Palo Alto, Calif.-based networking giant Friday said it will begin to sell a standalone version of its Solaris 9 server operating system for non-Sun hardware.

The software, based on Intel x86 chip architectures, is expected to ship in January for $99 for a single CPU system. Sun said there will also be a $20 "early access" edition for testing purposes. Previous versions of the Solaris OS for x86 were included for free as part of the company's Media Kit.