Yup, you read that right. Microsoft is making SQL Server, its popular Windows Server-based database, available for the open source Linux operating system.

Scott Guthrie, executive vice president for Microsoft’s Cloud and Enterprise Group, announced the news in a blog post on Monday, complete with quotes from executives at Red Hat rht and Canonical, two businesses that back popular versions of Linux.

This is blockbuster stuff if you have followed Microsoft msft from its pre-Satya Nadella days when Linux was not just viewed as the enemy but likened to cancer, by then chief executive Steve Ballmer.

Microsoft’s goal is to provide a “consistent data platform across Windows Server and Linux, as well as on-premises and cloud,” a Microsoft spokeswoman told Fortune via email.

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The idea now is to bring the core pieces of SQL Server, the basic relational tools, to Linux in a beta preview, available today. The product should be generally available by the middle of next year.

Read Satya Nadella’s Q&A with Fortune.

Still, this is a huge step for Microsoft. It’s been talking about its Azure cloud as a home for open-source and non-Windows software for a few years. But to make one of its key server applications available on an operating system other than Windows Server is a shocker. It was unclear when and if “non-core” SQL Server features would be brought to Linux.

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SQL Server has been a big success for Microsoft—especially in small and medium-sized businesses as well as within departments at bigger companies.

Still, it lags database kingpin Oracle orcl for the biggest accounts. Oracle’s databases are the de facto standard among Fortune 500 companies in the financial services, insurance, pharmaceutical and other industries. Oracle’s database runs on Unix, Linux, and Windows Server operating systems.