The Cisco UCS Chassis needs to be populated by "Cisco" blades. Much like HP and IBM Chassis needs to be populated with their respective vendor's blades. (I believe there is one vendor that allows 3rd party blades, but it's not very popular. Imagine the compatability & support concerns with a setup like that.)
Despite the form factor differences, trying to integrate a non-Cisco server into UCS would be the equivelant if trying to install the latest Intel i7 processor in an old x86 PC. The architecture's are completely different and the technologies used in the Cisco blades are far advanced. Being able to completely manage network, storage, and stateless compute systems from a single interface is something that requires advanced operations & communication between the management system, chassis and blades. Following this standard requirement of most blade manufacturers allows them to build powerful systems without being limited by compatability & timing restraints.
The UCS system can also manage Cisco rack servers as well. This is something no other vendor is able to offer. One pane of glass to manage all of your compute infrastructure!
Regards,
Robert
