ISO IEC 14776-321-2002 PDF

Full title and description

Information technology — Small Computer System Interface-3 (SCSI-3) — Part 321: SCSI-3 Block Commands (SBC). This International Standard specifies the functional requirements, device models and command set extensions used for SCSI block logical units (direct‑access devices, write‑once devices, optical block devices) so they can be attached to and used by computer systems.

Abstract

This part of ISO/IEC 14776 defines the SCSI-Block Command set (SBC): a logical unit model for SCSI block devices and the SCSI commands and parameters that apply to those devices. SBC enables attachment and coordinated use of block storage devices (flexible disks, rigid disks, optical disks, etc.) and includes commands for device management, data transfer and features to assist coordination between multiple operating systems.

General information

• Status: Published (International Standard).
• Publication date: 26 August 2002 (Edition 1, 2002-08).
• Publisher: Joint publication by ISO and IEC (ISO/IEC JTC 1/SC 25).
• ICS / categories: 35.200 (Interface and interconnection equipment).
• Edition / version: Edition 1 (2002).
• Number of pages: 132 pages (as published).

Scope

The standard specifies the command set extensions and device model necessary to operate SCSI block logical units and to permit application clients to communicate with devices that report themselves as direct‑access, write‑once or optical memory devices. It covers command definitions, parameter formats and behaviors required for block-device operation and describes how these clauses work together with the SCSI primary commands to define the complete SCSI block device command set.

Key topics and requirements

• Definition of the logical unit model for SCSI block logical units (addressing, block concepts, device types).
• Specification of SCSI block commands for data transfer and device control (read/write, management commands and parameters).
• Command and parameter semantics to support multiple operating systems and concurrent access (task/command coordination features).
• Device‑type specific behaviors (direct‑access, write‑once, optical) and differences between block device classes.
• Normative definitions, optionality/mandatory keywords and examples (e.g., XOR and block operations) to guide implementers.

Typical use and users

Implementers of SCSI storage device firmware and host‑side SCSI stacks, storage system architects, OS kernel developers, device driver authors, test labs and conformity assessors use this standard to ensure interoperable behavior of block storage devices and hosts. Product teams building disk drives, optical block devices, storage arrays and SAN/NAS components consult SBC when implementing SCSI block command behavior.

Related standards

ISO/IEC 14776 is a multi‑part SCSI family. Key related parts include the SCSI primary/primary‑commands documents (SPC family), SCSI Block Commands — 2 (ISO/IEC 14776-322:2007, SBC-2) and SCSI Block Commands — 3 (ISO/IEC 14776-323:2017, SBC-3), SCSI controller/management parts (e.g., 14776-341) and architecture model (14776-411). Many device‑type specific parts (for example 14776-381 for optical memory cards) reference and must be used together with SBC and SPC clauses. Implementers should consult the corresponding SPC and later SBC revisions for the most current command semantics.

Keywords

SCSI, SCSI-3, SBC, block commands, block device, direct‑access device, logical unit, SCSI commands, storage, device model, SPC, SAM.

FAQ

Q: What is this standard?

A: ISO/IEC 14776-321:2002 is the SCSI-3 Block Commands (SBC) standard that defines the block device model and command set extensions for SCSI block logical units.

Q: What does it cover?

A: It covers the logical unit model for block devices, the SCSI block commands and parameters, device‑type behaviors (direct‑access, write‑once, optical) and coordination semantics used when hosts and devices exchange block I/O commands. The clauses work in conjunction with the SCSI primary commands to form the complete SCSI block device command set.

Q: Who typically uses it?

A: Firmware and driver engineers, OS kernel and storage stack developers, storage system architects, hardware vendors, and test/conformance labs use this standard when implementing or validating SCSI block device behavior.

Q: Is it current or superseded?

A: ISO/IEC 14776-321 was published in 2002 and remains a published International Standard; however, the SBC family has later revisions and extensions (notably SBC-2 — ISO/IEC 14776-322:2007 and SBC-3 — ISO/IEC 14776-323:2017) that update and extend block command definitions for newer implementations. For new designs and the most current command semantics you should consult the later SBC revisions and the current SCSI Primary Commands (SPC) documents.

Q: Is it part of a series?

A: Yes — ISO/IEC 14776 is a multi‑part SCSI family (SBC is one part). Related parts include the SPC (primary commands), SAM (architecture model), SCC (controller commands), SSC (stream commands) and many device‑specific parts; these are intended to be used together to specify full SCSI device behavior.

Q: What are the key keywords?

A: SCSI, SBC, SCSI-3, block commands, logical unit, direct‑access device, SPC, SAM, storage, device commands.