Overview
ISO/IEC 14776-346:2024 - "Information technology - Small computer system interface (SCSI) - Part 346: Zoned Block Commands - 2 (ZBC-2)" defines the model and command set extensions needed to operate zoned block devices. Implemented together with the applicable clauses of SPC-6 and SBC-5, this International Standard specifies the standard SCSI command set and behaviors required for interoperable zoned block device operation.
Key topics and technical requirements
This part of the ISO/IEC 14776 series addresses core technical elements required to manage and use zoned block storage:
- Zoned block device model - formal model describing zones, their lifecycle and constraints.
- Zone types and conditions - classifications and state machine concepts that govern zone behavior.
- Zone attributes - metadata and descriptors that identify zone properties and capabilities.
- Zone operations and actions - command semantics for manipulating zones (for example: open, close, finish, reset and related operations as defined in the standard).
- Reporting and discovery - mechanisms for reporting zone layout, attributes and status to hosts.
- Write pointer features - requirements for managing sequential write pointers and rules that affect write ordering and permitted operations.
- Initialization, allocation and access rules - constraints for read/write and zone lifecycle transitions, including models requiring sequential writes.
These topics are specified as command set extensions and normative behaviors to be applied in conjunction with SPC-6 and SBC-5.
Practical applications and who uses this standard
ISO/IEC 14776-346:2024 is intended for stakeholders who design, implement or integrate zoned block storage:
- Storage device manufacturers - to implement compliant SCSI command extensions for zoned devices.
- Firmware and controller developers - to enforce zone models, write pointer rules and command semantics.
- Operating system and driver authors - to support zoned device discovery, reporting and correct host-side command flows.
- Storage vendors and integrators - for ensuring interoperability across hosts and devices in data center deployments.
- Test labs and certification bodies - for interoperability and conformance testing against the ZBC-2 specification.
Adopting the ZBC-2 command set enables reliable, standardized management of zoned block devices and supports ecosystem interoperability.
Related standards
- SPC-6 (SCSI Primary Commands) - referenced for core SCSI behavior and common command semantics.
- SBC-5 (SCSI Block Commands) - provides base block command definitions used together with ZBC-2.
- Other parts of the ISO/IEC 14776 series provide additional SCSI-related specifications.
Keywords: ISO/IEC 14776-346:2024, ZBC-2, Zoned Block Commands, SCSI zoned block devices, SPC-6, SBC-5, zone model, write pointer, zone operations.