ISO/IEC 14776-150:2004

Overview

ISO/IEC 14776-150:2004 - Information technology - Small Computer System Interface (SCSI) - Part 150: Serial Attached SCSI (SAS) specifies the functional requirements for the Serial Attached SCSI (SAS) physical interconnect and associated transport protocols. The standard defines a SAS interface that is compatible with the Serial ATA (SATA) physical interconnect, and describes three transport protocols: one for transporting SCSI commands, one for transporting SATA commands to multiple SATA devices, and one for interface management. It is intended to be used together with SCSI and ATA command set standards.

Key topics and technical requirements

The standard covers detailed technical areas essential for interoperable SAS implementations:

• Architecture & topology: ports, phys, devices, domains, expanders, pathways and connections.
• Physical layer: cables, connectors (internal/external/backplane), backplanes and passive interconnect requirements.
• Electrical characteristics: transmitter/receiver specs, impedance, eye masks, jitter and compliance points.
• Phy layer: 8b10b encoding, character encoding/decoding, bit ordering, out‑of‑band (OOB) signals and phy reset/negotiation sequences.
• Transport protocols: SCSI-over-SAS transport, transport of SATA commands to multiple devices, and management/maintenance protocol.
• Device management and discovery: SAS addressing, device/port identifiers, hashed addresses and expander routing/discovery.
• State machines & reset behavior: transmit/receive state machines, hard reset sequences, and I_T nexus loss handling.
• Expanders & routing: expander device models, connection managers/routers, broadcast primitive processing and route table methods.
• Ancillary items such as READY LED electrical characteristics, spread spectrum clocking and test patterns.

Applications and who uses it

ISO/IEC 14776-150:2004 is essential for:

• Storage hardware designers implementing SAS controllers, host bus adapters (HBAs), backplanes, cables and connectors.
• Firmware and driver engineers implementing SAS/SATA transport, phy management, and reset/state machine logic.
• System architects and integrators building enterprise storage arrays, servers and SAN/NAS solutions that require SATA compatibility via SAS.
• Compliance and test labs validating electrical, timing and protocol compliance (eye masks, jitter, OOB, 8b10b encoding).
• Component manufacturers (expanders, connectors, cable assemblies) ensuring interoperability across SAS ecosystems.

Related standards

• SCSI command set standards (used in conjunction with SAS transport)
• ATA / Serial ATA (SATA) physical and command set standards (compatibility and transport)
• Other parts of the ISO/IEC 14776 series covering SCSI interfaces and transports

Keywords: ISO/IEC 14776-150:2004, Serial Attached SCSI, SAS, SCSI, SATA compatibility, SCSI-over-SAS, physical interconnect, 8b10b encoding, expanders, connectors, storage interface standards.