Overview
ISO/IEC 14776-253:2023 - USB attached SCSI - 3 (UAS-3) is the first-edition international standard (published April 2023) that belongs to the ISO/IEC 14776 SCSI family. Prepared via INCITS (as INCITS 572-2021) and adopted by ISO/IEC JTC 1, this part defines how the Small Computer System Interface (SCSI) command set and behaviour are carried over USB using the UAS-3 transport. The document supports consistent implementation, interoperability and conformance for SCSI over USB devices and hosts.
Key topics and technical scope
Based on the published table of contents and editorial structure, the standard addresses technical elements common to UAS protocol specifications, including:
- Normative references, definitions, symbols and abbreviations - foundational terms and referenced documents used throughout the standard.
- Device and descriptor definitions - USB device, configuration and interface descriptors relevant to UAS devices.
- Transport and packet structure - layout and handling of transport packets for carrying SCSI commands and responses over USB.
- SCSI command mapping and processing - how SCSI commands, task management and command-response flows are encapsulated and sequenced.
- Data transfer mechanisms - directions and semantics for DATA IN / DATA OUT operations and bulk/streaming behaviors.
- Error handling and status reporting - reporting of SCSI sense data, transport error conditions and recovery actions.
- Task, reset and power management - task management functions, device resets, power/fault considerations and expected behaviours after events like power loss.
- Conformance and interoperability considerations - testing, transport packet constraints and recommended behaviors to ensure cross-vendor compatibility.
(These topics reflect the document’s content headings and the practical areas the standard governs; detailed protocol fields and numeric parameters are specified in the normative text of the standard itself.)
Applications and users
ISO/IEC 14776-253:2023 is intended for professionals and organizations involved in design, development and procurement of USB‑attached storage:
- Device manufacturers - SSDs, HDD enclosures, USB bridges and embedded storage modules implementing UAS‑3.
- Firmware and driver engineers - host-side drivers and device firmware ensuring correct SCSI-over-USB behaviour.
- System integrators and OEMs - ensuring interoperable storage interfaces across platforms.
- Test labs and conformity assessors - interoperability and compliance testing against the UAS‑3 specification.
- Standards and procurement teams - specifying requirements for USB Attached SCSI compliance in product RFPs and documentation.
Related standards
- ISO/IEC 14776 series (SCSI family)
- Relevant USB specifications and vendor driver/stack guidelines
- INCITS / ANSI contributions referenced in the standard
Keywords: ISO/IEC 14776-253:2023, UAS-3, USB Attached SCSI, SCSI over USB, storage protocol standard, device interoperability, firmware, driver development, conformance.
Open preview (PDF)Information technology — Small Computer System Interface (SCSI) — Part 253: USB attached SCSI - 3 (UAS-3)
