A good article at the blog Techanalyst Talks (http://techanalysttalks.blogspot.com)

Cisco this week extended its Unified Computing System data center convergence platform with rack mountable servers, saying the new form factor represents an "entry level" into UCS and more choice for customers..

When Cisco first announced its Unified Computing System (UCS) product portfolio earlier this year it was all about its 'B' series blade servers. Now Cisco is expanding its UCS product portfolio with a new 'C' series that includes three new rack servers, which are officially being announced at its Partner Summit now underway in Boston. Like the predecessor B-Series blades, the C-Series rack mount servers use X86 Intel Xeon 5500 processors and are optimized for Cisco's memory expansion and virtualized adapter technologies,

The addition of the UCS C-Series rack-mount servers to Cisco's data center strategy, which has seen the launch of a total of six products in the past 18 months, broadens the reach of its UCS, offering an entry point to the architecture while providing an upgrade path to full UCS attributes. UCS, which was launched in March, is Cisco's next-generation data center architecture that combines servers, storage access, virtualization and the network into a single fabric managed by one system.

UCS is designed to tightly integrate computing, networking, storage access and virtualization into a single platform. It features memory extension technology for scaling virtual machines (VM); virtual adapters to reduce the number of physical adapters in a server; embedded management; and service profiles designed to stay with a VM as it moves around an enterprise.

These Cisco advances rule out the participation of non-Cisco blade and rack servers in a UCS environment. Cisco has said previously that it has no plans to open up UCS to incumbent data center servers from Hewlett-Packard Co., IBM, Dell Inc. or Sun Microsystems Inc.