Cisco's Unified Computing System (click for larger image)

Cisco may have made headlines this week with the debut of its first computer server for data centers, but it's EMC's VMware unit that made out like gangbusters.

The announcement -- previously called "California" -- was the internal code name for a joint Cisco-EMC project. The first big result of the project is Cisco's Unified Computing System (UCS), which ties together network management, virtualization, and storage in a blade-server form factor.

With VMware as the key connective tissue between Cisco and EMC, a steady flow of cooperative products and services are expected to be announced in coming weeks and months. The partnership isn't exclusive, however, as Cisco said its UCS hardware will be able to run Citrix Systems or Microsoft hypervisors as well.

While EMC and Cisco have cooperated for years, the two companies became serious partners in July 2007, when Cisco invested $150 million in VMware before the software virtualization company launched its IPO. In an interview Wednesday, EMC's Chris Gahagan, senior VP of resource management, said EMC and Cisco's virtualization drive will create "private clouds" for data centers and enterprise installations.

"It's really about how you want to run your data center," said Gahagan who argued that virtualization as presented in UCS will pretty much eliminate the need to redo software applications. "The challenge is whether you have to rewrite all your applications. Now with Cisco's UCS you get what looks like a virtual computer. The power of this whole thing is that customers don't have to rewrite their applications."