Hi,
I found an interesting article about Platform layer for SQL Server. It talks about SQLOS. As I understand it is an abstraction layer between the hardware and SQL Server. So does it mean that we can have SQL Server installed without installing windows? It sounds very strange to me... Please tell me where it is possible to find more info on this. And also whoever have used SQLOS and for what reason? What are the main advantages from developers view?
I don't think SQLOS will replace Windows OS. SQLOS is an abstraction layer that manages SQL Server and it is an OS in a way that it contains an API that allows developers to communicate with SQL Server. I don't think it is an OS in the sense that it's the first thing you install on a system.
SQLOS is a user mode OS. It handles cooperative multitasking inside a process, memory allocations and IO, in a highly scalable manner. Slava has a number of articles on his blog explaining some of the details how SQLOS works. To better understand why is a need for a user mode OS, I'd also recommend going through Rick Vicik's series of articles on High Performance Windows programs. SQLOS is not designed for end user application development (ie. apps that can be written using the CLR Tasks library) but instead is targeting the infrastructure those applications run on (ie. it is designed to implement the native part of the said Tasks library).
Note that SQLOS still needs the services of a 'true' operating system to handle the interaction with the underlying hardware (CPU, Memory, Disk).