ISO/IEC 14776-415:2019 defines a reference model that specifies common behaviors for SCSI devices, and an abstract structure that is generic to all SCSI I/O system implementations.The set of Small Computer System Interface (SCSI) specifies the interfaces, functions, and operations necessary to ensure interoperability between conforming SCSI implementations. This document is a functional description. Conforming implementations employ any design technique that does not violate interoperability.The following concepts from previous versions of the SAM standard are made obsolete by this version:a) support for the SPI-5 SCSI transport protocol;b) Contingent Allegiance;c) the TARGET RESET task management function;d) basic task management model;e) untagged tasks; andf) linked command function.