ISO/IEC 14776-151:2010

Overview

ISO/IEC 14776-151:2010 (SAS-1.1) - Information technology - Small Computer System Interface (SCSI) - Part 151: Serial Attached SCSI‑1.1 - is an international functional specification that defines rules for exchanging information between SCSI devices using a serial interconnect. The standard also specifies the rules for exchanging information between ATA hosts and ATA devices over the same serial interconnect, and it defines architecture, naming, and behavioral models to ensure interoperability. Conforming implementations may use any design techniques that preserve interoperability.

Key topics and technical requirements

ISO/IEC 14776-151:2010 is a comprehensive functional description covering the Serial Attached SCSI (SAS-1.1) environment. Major technical topics include:

• Architecture and device models: SAS device, port, phy, expander models and service delivery subsystems.
• Physical layer and passive interconnects: definitions for SAS and SATA connectors, cable assemblies, internal/external connectors and pin assignments, backplane and fan‑out cable types.
• State machines and protocol behavior: transmit/receive data path state machines, reset behavior (hard/reset), I_T nexus loss handling and message sequencing.
• Expanders and routing: edge and fanout expander device models, Expander Connection Manager (ECM), Expander Connection Router (ECR), broadcast primitive processor (BPP), routing attributes and route tables.
• Discovery and topology: discovery processes, allowed topologies, discover optimizations and expander route index ordering.
• Names, identifiers and addressing: SAS addresses, hashed addresses, device/port/phy identifiers and naming conventions.
• Test functions and diagnostics: phy test functions and procedures for verifying link integrity and interoperability.
• Interoperation with ATA/SATA: rules enabling ATA hosts and devices to use the same serial interconnect while maintaining compatibility with SAS devices.

Practical applications

This standard is essential for designing, implementing, testing and documenting serial storage subsystems where interoperability and predictable behavior are required:

• Hardware engineers designing SAS controllers, expanders, backplanes and cable assemblies
• Firmware and driver developers implementing SAS state machines, discovery and routing logic
• System integrators and OEMs building storage enclosures and server storage backplanes
• Test labs and QA teams validating connector pinouts, phy tests and protocol compliance
• Data center architects specifying interoperable storage components

Who should use this standard

• Manufacturers of SAS controllers, drives and expanders
• Firmware and driver developers for storage subsystems
• Compliance and interoperability test houses
• Standards professionals and technical writers documenting storage products

Related standards

• Other parts of the ISO/IEC 14776 SCSI series (Serial Attached SCSI parts)
• SATA/ATA interface specifications for related ATA device interoperation

Keywords: ISO/IEC 14776-151:2010, SAS-1.1, Serial Attached SCSI, SCSI, SAS connectors, SAS expanders, SATA compatibility, phy test, storage interconnect.