SSDs are encroaching on hard disk drives with the promise of faster access to data, but HDDs are fighting back -- in some cases, with built-in solid-state storage of their own. On Tuesday, Seagate Technology took the fight to the enterprise market, introducing its Seagate Enterprise Turbo SSHD, which it calls the world's first enterprise hybrid drive. Shipping now to server and storage vendors and resellers, the new drive is also available as an option in IBM System x servers.