Federal agencies have begun the long march to cloud -- moving selected portions of their data processing work into the Internet cloud, prompted in large part by an Obama administration "Cloud First" mandate initiated last year.

Some of that work--from computing infrastructure on demand to software delivered as a service--is already being provisioned by commercial providers, including Amazon's Elastic Compute Cloud (EC2), as well as Google, Microsoft and others.

But the reality is, most federal agencies are choosing to take their first steps into the federal cloud computing future by moving into private clouds--data processing and storage centers that are physically, not just virtually, dedicated to serving the federal government. Ind in many cases, those data centers are under such intense security controls, even agency personnel are restricted from entering into their inner computing chambers.

AOL Government contributing writer Dan Verton, however, was recently granted a rare visit to "The Vault," one of the most secure cloud hosting facilities in the country, designed to meet the federal government's exacting standards for a commercially-managed, dedicated government data center facility.

Housed near Dulles, Va., Carpathia Hosting Inc.'s data center handles cloud services for more than 20 federal agencies, including several from the national security community.

With concentric rings of security, biometric access points, armed guards, and nearly-impenetrable Lampertz vaults, physical security of The Vault data center is truly impressive.

Each agency server is housed in its own segregated vault, which is capable of protecting it from fire and water, and even electromagnetic pulses that could fry the electronics.

The company's defense-in-depth strategy for comprehensive physical, network, and policy-based security assures customers that even their most sensitive data will remain secure and available. Since it became operational more than six years ago, The Vault has delivered an impressive 100% uptime record.

In fact, the facility is so secure that even customers are rarely granted access. Visitors are not allowed to park inside the gated complex and must be cleared to visit at least 24 hours in advance by Carpathia's own security guard force – a guard force with arrest powers.

AOL Government was allowed a rare opportunity to visit the facility and tape an interview with two of Carpathia's senior executives. But even with the approval of senior managers to visit the facility, we were never able to get close to the actual data vaults where only a trusted few Carpathia employees have access to the servers.

Ask 10 people to define cloud computing, and you will likely get 10 different answers, says Michael Fox, director of Carpathia Government Solutions, in an interview. One thing cloud computing is not, he says, is an ungoverned, unprotected place somewhere in the boundless Internetsphere.

As AOL Government recently discovered during our visit to the Carpathia Hosting center, reportedly the largest commercial Sensitive Compartmented Information Facility (SCIF) in northern Virginia, a cloud computing data center is anything but ungoverned and unprotected.

In the following video segment, Dan Verton offers us a 3D virtual tour of The Vault based on his visit and commentary by Mike Clemson, Carpathia's senior director for facilities.