Just when you think the operating system space is about as saturated as it could get — and all the action has moved to the middleware and applications layers of the stack — there’s a new OS added to the mix.

Unlike most OSes, however, the new OS, called Cosmos, doesn’t run on the bare metal of machines. Rather, it’s a virtualized OS that runs within the .NET container, intended to support .NET-based languages (particularly C#) that are also resident on the .NET container. Cosmos stands for “C# Open Source Managed Operating System.”

The OS is also open source, issued under the BSD license.

Why develop Cosmos? Actually, Microsoft also has a .NET-based OS called Singularity that also runs within this environment. The reason stated in the Cosmos FAQ section is that:

“Primarily because it’s fun. But beyond that, how else can you boot .NET on a floppy or small USB stick? Who else will try to put .NET on the Wii, OLPC, and iPhone? We are also developing a TCP/IP stack. Imagine instead of deploying half a dozen virtualized OS’s, deploying many dozens of dedicated OS’s. One that only does DNS, a few that only do HTTP, etc. One instance, one function.”

Welcome to the party, Cosmos. Mary Jo Foley, who first uncovered this announcement, also spoke with Chad “Kudzu” Hower, a former Microsoft employee, who admitted the OS has a “super geeky” flavor to it, and even has garned independent interest from Microsoft staffers.

It’s no secret that Cisco Systems sees data center management in it’s future, beyond simply being a hub-router-switch vendor. Cisco’s strategy for the past few years has to promote the idea of moving intelligence off the server and out onto the network.

For example, Cisco has been promoting its Service Oriented Network Architecture (that’s SONA, not SOA), intended to abstract network functions — such as switching, security and storage — to a more manageable and uniform service layer.

Now, the vendor has unveiled what analysts see as a bold move to take control of the data center once and for all. Cisco announced a family of data center-class switching platforms , the Cisco Nexus Series, designed, the vendor says, for “next-generation mission-critical data centers.”

At the heart of the announcement is the Cisco Nexus 7000 super-switch, which combines Ethernet, IP, and storage capabilities across one unified network fabric. This monster supports 15 terabits per second of switching capacity in its chassis, with room for 512 10-Gbps Ethernet, and the capability of upgrading to 40 and 100 Gbps.

As one analyst explained: “Most data centers have a separate network for high-performance clusters and a network for storage. Cisco is saying you don’t need all these different network silos. You can have one network to support everything.”

Maybe Sun was right all those years ago — the network is the computer.

Last May, I posted details on a novel approach to data center flexibility — offering data centers-in-a-box, in the form of fully loaded and equipped portable trailers that could be pulled right up into corporate parking lots and plugged in. IBM, Sun, and even Microsoft were talking up such mobile approaches.

Kind of a neat idea, but I wondered at that point if in this age of emerging software-as-a-service, on-demand, and in-the-cloud com­puting approaches, were such bolt-on facilities really needed?

Plus, another trend working against trailer DCs is the increasing compute power constantly being packed into smaller and denser chips, as well as geometrically growing stor­age capacity that shows no signs of abating. It’s not inconceivable that all the func­tions of an average data center could eventually be packed into a box the size of a desktop computer. IBM’s System z was proof in point — these powerful boxes have relatively small footprints compared to mainframes of old.

Well, Sun Microsystems, which has been making a big deal out of its Project Blackbox, reports that it has signed on about four or five customers. These include the Stanford Linear Accelerator Center (SLAC), Hansen Transmissions, Radboud University Nijmegen Medical Centre (UMCN) and Mobile TeleSystems OJSC (MTS).

You could look at the announcement in terms of the glass being half full or half empty (or better yet, one percent full, 99% empty.)

One industry commentary puts it in the 99% empty perspective, pointing out that in the 15 months Sun has been pushing this trailer approach, it has only signed on four or five customers. That doesn’t seem like an exciting value proposition for vendors contemplating this space, or for companies that want to see how the approach working out in reality.

For end user IT managers, perhaps, as one commenter to the report pointed out, “the real answer is to update your existing datacenter vs. branching out to the parking lot.”