Extending an open hand to each other instead of a clenched fist, archrivals Hewlett-Packard and Sun Microsystems have agreed to ensure that a couple of their bread-and-butter server products work smoothly together.

Under the terms of the multiyear agreement, HP will distribute Sun's Solaris 10 operating system on its best-selling ProLiant servers as well as its blade servers, and supply technical support. HP has also agreed to sell both one- and three-year standard and premium subscriptions for Solaris.

The deal elevates Sun to a strategic partner for HP's ProLiant servers and also lays the groundwork for the two to create exposure for both Solaris and OpenSolaris among new users. It could also help each in its battle with a common enemy: IBM.

The agreement could increasingly draw HP further into the open source world. The company said it plans to increase its participation in the OpenSolaris community by collaborating with other users on the development of new features as well as improving interoperability. HP already makes Red Hat's market-leading version of Linux available on its servers.

Traditionally fierce rivals in the Intel and Unix-based server markets, the deal may be an admission on HP's part that Sun continues to have a substantial presence on a wide variety of hardware platforms, including those of HP and Compaq.

"It's a little-discussed secret that Solaris enjoys the largest installed base of any commercial Unix or Linux distribution," said Jesse Freund, an analyst relations manager with Sun. "It is also true that the Solaris OS is supported on more than 1,000 platforms, with more than 150 HP/Compaq systems on Sun's Hardware Compatibility List."

John Fowler, Sun's executive VP in charge of systems, admits that HP's endorsement of Solaris on ProLiant systems does indeed significantly expand the available market for the operating system on Intel-based hardware. He believes the robust ecosystem that surrounds Solaris will help accelerate its adoption.