Justin Sullivan, Getty Images

Time was when Microsoft executives thought nothing about publicly dissing open-source software as distinctly un-American.

Everyone has their pet theories. Some even drew a direct line back to the company's early days dating to 1976, when co-founder Bill Gates published an open letter chiding hobbyists for using Microsoft's Altair Basic program without paying for the product. By the time open source began gaining notoriety in the late 1990s and early 2000s, Microsoft saw a threat to the way it sold software and services and went on the PR offensive -- with no small amount of hyperbole.

''Open source is an intellectual-property destroyer,'' former Windows chief Jim Allchin famously quipped in 2001. ''I can't imagine something that could be worse than this for the software business and the intellectual-property business.''

"Linux is a cancer that attaches itself in an intellectual property sense to everything it touches," former Microsoft CEO Steve Ballmer told the Chicago Sun Times a few months later. "That's the way that the license works."

But Microsoft's feud with open source has been sputtering for quite some time, and the senior managers who led the anti-open source charge are gone from the scene -- or at least no longer in positions of authority. Open source is now routinely used by corporations around the world, and the company's sniffy put-downs only fed into the perception of Microsoft as out of touch.

Some of that new thinking reflects the change at the top of the corporate pyramid, with Satya Nadella replacing Ballmer as CEO in early February. Since taking over, Nadella has talked up his vision of a Microsoft whose future isn't shackled to its Windows past.

"There has been a real change," said Forrester analyst Jeffrey Hammond, noting that while that shift hasn't yet permeated the entire Microsoft organization -- particularly the Windows team -- "it's seeped into enough of the organization that it's more than just window dressing. There are many examples where Microsoft is integrating with, and even creating, open source in an effort to grow market share and support customers.

"The reason is simple," he continued. "The real world isn't black and white -- and there are open-source companies that sell proprietary software (e.g., Red Hat) and proprietary companies that use OSS to augment their commercial software and make it more attractive. As developer adoption of open-source software has grown to the 70 percent-plus level, I think most business units at Microsoft realized that treating it like 'a cancer' was self-defeating -- they lost that battle a long time ago."

Given the new tech realities, Microsoft will just have to pick and choose. Sometimes, it will be better off investing in collaborative, open-source projects like Hadoop or Git that win widespread adoption. Other times, Microsoft will be better off competing head-on as it does with Office vs. Open Office.

Last month, the company finally made official its unofficial decision to incorporate some open-source code into its developer and programming languages. More recently, Microsoft put 22-year company veteran Mark Hill in charge of a global group to cultivate open-source developers to write applications that work with Azure, the Microsoft cloud service that competes against the likes of Rackspace, Google, and Amazon.

I recently spoke with Hill. The following is an edited transcript of our conversation.

Cooper: There was a time when open source was considered an "intellectual-property destroyer," as Jim Allchin once referred to it. What are the new marching orders, and why the change?

Hill: We have a group of individuals who are residents around the world who are open-source practitioners that we've recruited from the community. They are our subject matter experts, and they've been helping us engage -- and help Microsoft become more aware of that community...But given their healthy knowledge of open source and their connections, we're changing roles to try and make Microsoft more responsive and to make sure that we appeal to that community at large.

With the aim being -- what?

Hill: We want make sure that we give (developers) the tools, training, and advice they'd need to run open-source tools on Azure. It's a great platform for them to build their business, and we want to give them everything they need to be successful.

When was the new direction formalized?

Hill: It's been ongoing for a long time. The fact that Azure supports a bunch of open-source apps and frameworks and languages -- that's not new news. It's maybe just a natural evolution...where we want to go out and activate the ecosystem to start using Azure. There's a big (potential) business out there.

And the goal is to win over open-source developers to port their apps on Azure? How do you go about that? What can Microsoft offer?

Hill: All the basics that you would in any IT business. Let's look at the competing value propositions. What are the details? Do we have the right advice, support, and learning? Do we have some free sample code that they can get to and test before they invest? Can we introduce people who are interested to people who have done this before?

There was a CSI job posting in December where the advertisement was "Win share against Open Source Software (OSS) in the cloud, on devices, and in traditional workloads by changing perceptions of Microsoft and winning the socket." So what are the rules of engagement? That is, where does it make sense for Microsoft to compete with open-source products, and where does it make sense to partner? It sounds as if you'll still compete in certain areas but that this isn't viewed any longer as something of a holy war where open source is seen as something evil. Or am I simplifying?

Hill: I don't think that you're oversimplyfing. You're completely correct in terms of there being a mindset change. We'll compete against certain products that are open-source products. But it's not about open source [per se]. For example, we'll compete against Linux when we feel that Windows Server is a better product for the customer or partner. In other cases, we'll certainly want to partner; it's just good business.

Steve Ballmer's no longer the CEO. What's Sayta Nadella's role in pushing for the mindset change?

Hill: I would just say that as a company, Microsoft is very forward-looking and we understand that in a devices and services world, the game needs to change. Many years ago, we began building in very good support for Linux and open source in Azure and this is just a continuation of that. Again, we need to appeal to a very broad market.