Chapter 7. OS and Hardware Interaction

In this final chapter, we reach the lowest level of the SQL Server engine, namely the SQL Server Operating System (SQLOS) layer. The SQLOS manages many functions and services in the engine, but the two primary ones are the scheduling of task execution (i.e. CPU time) and the allocation and management of memory across all SQL Server data engine components.

Books Online lists 29 objects in the "sys.dm_os_" category, which collectively can provide us with a vast amount of detailed data (sometimes too much) regarding the nature of the interaction between SQL Server and the operating system. What we've tried to do in this chapter is to select the ten DMOs in this category that are likely to be the most immediately useful to DBAs in their normal tuning and system management activities. We'll answer common questions, such as those below (relevant DMOs are shown in brackets, minus the sys.dm_os_ prefix).