A detailed analysis of SAS© engines. The V9 (BASE) engine is the default SAS© engine for SAS© datasets. The document presents engines for big data and multi-threaded distributed processing (CAS, SPDE, Parquet, ORC), as well as engines for importing/exporting specific file formats (JSON, XMLV2) and accessing external databases via SAS©/ACCESS. It explains the different data access patterns (sequential, random, BY-group, multiple passes) and locking levels (library, member, record) essential for managing concurrent access and data integrity.