Looking for good, but quick references for underlying OS concepts related to SQLOS (Memory Access, Scheduling, etc...)?
This is a very broad quesiton and will be eventually closed.

Below page from BOL will be helpful to you :


Thread and Task Architecture
Platform layer for SQL Server - A new platform layer in SQL Server 2005 to exploit new hardware capabilities and their trends by Slava Oks
Architectural Overview of SQL Server 2014’s In-Memory OLTP Technology
SQL Server Threading Model - This is to Paul Randal's online course about wait stats on Pluralsight.