Mark Russinovich is a legendary figure in the computer industry. A former teenage hacker who went on to earn a PhD in computer engineering from Carnegie Mellon, Russinovich cofounded Winternals Software -- a Windows utilities vendor renowned for understanding the guts of Windows as well as Microsoft itself.

After a stint at IBM's Thomas J. Watson Research Center and after discovering a number of high-profile Windows security vulnerabilities, not to mention the infamous Sony rootkit, Russinovich joined Microsoft when Winternals was acquired in 2006. Russinovich is also an accomplished novelist, whose cyberthrillers Zero Day and Trojan Horse have been well received (the third novel in the series, Rogue Code, comes out this May).

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Today, Russinovich is a Technical Fellow, the highest technical position at Microsoft. He's the sole Technical Fellow in the Windows Azure Group, acting as lead architect for Microsoft's bet-the-company cloud initiative -- $15 billion have been invested in cloud infrastructure to date. Much of what Russinovich has been working on pertains to the complex automation necessary to manage that cloud infrastructure at scale. The interview began with an examination of Azure technology and moved to broader concerns about IT's march to the public cloud. The folllowing is an edited version.

InfoWorld: Tell us about some of the technology development you're currently involved in.

Russinovich: One of them is the compute platform -- that means down at the data center infrastructure as well as the servers, the virtual machine management and allocation algorithms and deployment, and the way that we create our IaaS virtual machines and our PaaS virtual machines. And then going up the stack it's kind of broader than just compute, and that is our application model [where] you'll start to see the first signs of our revamped cloud application model.

InfoWorld: Microsoft has made a huge investment in cloud infrastructure for both Azure and Office 365.

Russinovich: One of the things that the company is committed to is that all roads lead to Azure. So there are parts of Office 365 that actually run on Azure today. The goal is to eventually have everything running on Azure.

InfoWorld: I wasn't aware that Office 365 was migrating to the Azure platform, although that makes sense.

Russinovich: It's going to take awhile, just like all migrations do. But that's the direction the company and Satya Nadella have set.

InfoWorld: I would imagine your Dynamics software is going there as well?

Russinovich: Yes, it is.

InfoWorld: Were you involved, then, in developing Microsoft's multitenancy model of all of this?

Russinovich: Yes.

InfoWorld: A lot of the cloud is about faith. So from the outside it's not always clear exactly how the multitenancy architecture is laid out from company to company.

Russinovich: I think that's one place where we've been way more transparent than anybody else. I've given talks for three years since I joined Azure at TechEd and Build on Windows Azure Internals about how our virtual machine technology is implemented and how we implement that multitenancy. You don't see Amazon or Google talking about that.

InfoWorld: Could you give me a quick sketch?

Russinovich: Sure. When it comes to virtual machines, which are really the building blocks of the cloud, we've got pools of servers, we've got something called a fabric controller, which is like the brain.