What is SQLOS?

Chances are you've already installed the newest version of Microsoft SQL Server 2005 on one of your (testing) servers.

I find the 2005 version a great release feature and easy-of-use wise, but the release is also a great example of advanced software architecture.

For example, did you know that when you install SQL Server 2005, you are also installing a mini operating system (OS) onto your server?

Sure, a RDBMS is by definition some kind of application logic on top of a database file, but I think SQL Server 2005 takes this a big step further.

This operating system that "runs" SQL Server 2005 is called simply SQLOS. Slava Oks, a developer on the SQL Server team at Microsoft, defines SQLOS in his blog like this:

"SQLOS is a user mode operating system that leverages a hierarchical design similar to the hardware on which it runs."

What do you think? I think this is interesting. And yes, I confess I didn't know about this layer existed before. But there's an easy cure for that. Happy studies!