SCSI Standards Architecture (*)

(*) This chart reflects the currently approved SCSI project family. T10 is responsible for all projects, except: IEEE is responsible for IEEE 1394; T11 responsible for Fibre Channel; Internet Engineering Task Force (IETF) is responsible for iSCSI and the Internet; the InfiniBand Trade Association is responsible for InfiniBand (tm); and the USB Implementers Forum, Inc. is responsible for the Universal Serial Bus (USB).

Note that the original third-generation SCSI standards used the name SCSI-3 to distinguish them from SCSI-2. Subsequent SCSI standards have dropped the '-3' from their names because it was cumbersome. So, when the SCSI-3 Architecture Model (SAM) was revised, it became the SCSI Architecture Model - 2 (SAM-2). While the individual components of the SCSI family continue to evolve, there is no SCSI-4 project envisioned.

DOCUMENT LINKS

SBC SCSI-3 Block Commands [first generation disk drive command set]
SBC-2 SCSI Block Commands - 2 [second generation disk drive command set]
SBC-3 SCSI Block Commands - 3 [third generation disk drive command set]
RBC Reduced Block Commands [simplified disk drive command set]
RBC_AM1 Reduced Block Command Set Amendment 1 [first amendment to above standard]
SSC SCSI-3 Stream Commands [first generation tape drive command set]
SSC-2 SCSI Stream Commands - 2 [second generation tape drive command set]
SSC-3 SCSI Stream Commands - 3 [third generation tape drive command set]
SSC-4 SCSI Stream Commands - 4 [fourth generation tape drive command set]
SMC SCSI-3 Media Changer Commands [first generation jukebox command set]
SMC-2 SCSI Media Changer Commands - 2 [second generation jukebox command set]
SMC-3 SCSI Media Changer Commands - 3 [third generation jukebox command set]
MMC Multi-Media Commands [first generation CD-ROM command set]
MMC-2 Multi-Media Commands - 2 [second generation CD and DVD command set]
MMC-3 Multi-Media Commands - 3 [third generation CD and DVD command set]
MMC-4 Multi-Media Commands - 4 [fourth generation CD and DVD command set]
MMC-5 Multi-Media Commands - 5 [fifth generation CD and DVD command set]
MMC-6 Multi-Media Commands - 6 [sixth generation CD and DVD command set]
SCC-2 SCSI Controller Commands - 2 [second generation RAID controller command set]
SES SCSI-3 Enclosure Commands [command set for enclosures (fans, power supplies, etc.]
SES_AM1 SCSI-3 Enclosure Commands Amendment # 1 [first amendment to above standard]
SES-2 SCSI-3 Enclosure Commands - 2 [second generation command set for enclosures (fans, power supplies, etc.]
OSD Object-Based Storage Devices [object-oriented (e.g., files) command set for disk drives]
OSD-2 Object-Based Storage Devices - 2 [second generation object-oriented (e.g., files) command set for disk drives]
OSD-3 Object-Based Storage Devices - 3 [third generation object-oriented (e.g., files) command set for disk drives]
ADC Automation/Drive Interface - Commands [command set for the Automation/Drive interface]
ADC-2 Automation/Drive Interface - Commands - 2 [second generation command set for the Automation/Drive interface]
ADC-3 Automation/Drive Interface - Commands - 3 [third generation command set for the Automation/Drive interface]

Primary Command Sets:

SPC-2 SCSI Primary Commands - 2 [second generation command set for all SCSI devices]
SPC-3 SCSI Primary Commands - 3 [third generation command set for all SCSI devices]
SPC-4 SCSI Primary Commands - 4 [fourth generation command set for all SCSI devices]

Architectural Models:

SAM SCSI-3 Architecture Model [first generation architectural model for SCSI devices]
SAM-2 SCSI Architecture Model - 2 [second generation architectural model for SCSI devices]
SAM-3 SCSI Architecture Model - 3 [third generation architectural model for SCSI devices]
SAM-4 SCSI Architecture Model - 4 [fourth generation architectural model for SCSI devices]
SAM-5 SCSI Architecture Model - 5 [fifth generation architectural model for SCSI devices]

Parallel Interface:

SPI-2 SCSI Parallel Interface - 2 [second generation parallel interface (Ultra2)]
SPI-5 SCSI Parallel Interface - 5 [fifth generation parallel interface (Ultra640)]

Parallel Interface Related Standards and Technical Reports:

SDV SCSI Domain Validation [technical report on discovering maximum supported speeds]
PIP SCSI Passive Interconnect Performance [standard on testing and measuring cables, connectors, etc.]
SSM-2 SCSI Signal Modeling - 2 [standard on modeling SCSI signals]
EPI SCSI Enhanced Parallel Interface [technical report on enhancements to the parallel interface]

IEEE 1394:

SBP-2 Serial Bus Protocol - 2 [second generation protocol for transporting SCSI over IEEE 1394]
SBP-3 Serial Bus Protocol - 3 [third generation protocol for transporting SCSI over IEEE 1394]

Fibre Channel (FC):

FCP Fibre Channel Protocol [first generation protocol for transporting SCSI over Fibre Channel]
FCP-2 Fibre Channel Protocol - 2 [second generation protocol for transporting SCSI over Fibre Channel]
FCP-3 Fibre Channel Protocol - 3 [third generation protocol for transporting SCSI over Fibre Channel]
FCP-4 Fibre Channel Protocol - 4 [fourth generation protocol for transporting SCSI over Fibre Channel]

Serial Storage Architecture (SSA):

SSA-S3P SSA SCSI-3 Protocol [protocol for transporting SCSI over SSA]
SSA-TL2 SSA Transport Layer - 2 [second generation SSA transport layer]
SSA-PH1 SSA Physical Layer 1 [first generation SSA physical layer]
SSA-PH2 SSA Physical Layer 1 [second generation SSA physical layer]

SCSI Remote Direct Memory Access Protocol:

SRP SCSI RDMA Protocol [protocol for transporting SCSI over RDMA interfaces, e.g., InfiniBand (tm)]

Serial Attached SCSI (SAS):

SAS Serial Attached SCSI [protocol and physical interface for transporting SCSI over serial links]
SAS-1.1 Serial Attached SCSI - 1.1 [SAS protocol and physical interface enhancements for transporting SCSI over serial links]
SAS-2 Serial Attached SCSI - 2 [SAS protocol and physical interface enhancements for transporting SCSI over serial links (up to 6 Gb/sec)]

Starting with SAS-2.1, the protocol and physical sections of SAS are split into separate standards.

Automation/Drive Interface:

ADT Automation/Drive Interface - Transport Protocol [protocol/transport principally for Automation/Drive Commands]
ADT-2 Automation/Drive Interface - Transport Protocol - 2 [second generation protocol/transport principally for Automation/Drive Commands]

USB Attached SCSI (UAS):

UAS USB Attached SCSI [protocol for efficient transport of SCSI commands over USB]

SCSI / ATA Translation:

SCSI / ATA Translation (SAT) is a software translation layer that maps ATA devices to make them appear to be SCSI devices:

SAT SCSI / ATA Translation [first generation of SAT]
SAT-2 SCSI / ATA Translation - 2 [second generation of SAT]
SAT-3 SCSI / ATA Translation - 3 [third generation of SAT]

About SCSI-2:

SCSI-2 is the predecessor to the SCSI-3 family of standards. It is a single standard containing all SCSI architecture layers for only the parallel interface. There is a companion standard for SCSI-2 called the SCSI-2 Common Access Method and SCSI Interface Module (CAM) that describes a layered software driver method for usage with SCSI-2. While most software drivers today do not exactly conform to CAM, they generally do follow its layered concepts:

SCSI-2 Small Computer System Interface - 2 [second generation of SCSI]
CAM SCSI-2 Common Access Method and SCSI Interface Module [software layering standard]

[Return to the T10 home page.]

For more information on T10 or if you have comments on this page contact John Lohmeyer