Microsoft SQL Server architecture consists of essential components: Database Engine (Relational Engine and Storage Engine), where the Relational Engine analyzes, optimizes, and executes queries, and the Storage Engine works with the file system, buffer pool, transaction log, recovery, locking. SQLOS manages memory and CPU, I/O, and plan cache. TempDB, master, model as system databases and filegroups, data and log files are vital parts of the architecture