hesela.devSCSI REPORT SUPPORTED OPERATION CODES
REPORT SUPPORTED OPERATION CODES is a SCSI command that queries a logical unit for supported commands or support details for a selected command.
Command identity may require an opcode and service action; interpreting its name may also depend on the peripheral device type. The sg_opcodes tool can request a list or one command's support data. Its --enumerate option only looks up a name and ignores the device; that is not a capability probe. [1]
A 2011 tape-drive interface reference distinguishes SUPPORT 0 (information unavailable), 1 (unsupported), 3 (standard-defined support) and 5 (vendor-specific support). Unavailable information is not evidence of non-support. This is a historical implementation reference, not an exhaustive current-SPC table. Operational implication: retrieving a support report does not prove that a later command will complete successfully. [2]
The --rctd option requests timing descriptors, which may be absent. Reported nominal and recommended timeouts use seconds; zero means no timeout is indicated, not instantaneous completion. These are timeout guidance, not measured workload latency. [1]
The historical T10 timeout proposal excludes delays outside the device server's control and warns against product comparisons using these values. It explains design intent, not current conformance requirements. [3]
Relations
- related
- SCSI, SCSI Primary Commands
Citations
- Doug Gilbert, sg_opcodes(8), source at 8799caa3741b2b1640970747aeb84f17dbbaad86: description, --opcode, --enumerate and --rctd
- Oracle StorageTek T10000 Fibre Channel Interface Reference, E20425-02 (July 2011), pp. 189-194: REPORT SUPPORTED OPERATION CODES
- Kevin Butt, T10/05-284r4 (8 November 2006), section 6.22.2: Self Describing Command Timeouts
Further reading
Sources & caveats
- Source-backed capability-discovery synthesis; pinned tool documentation, historical Oracle implementation and explicitly non-normative T10 proposal. No hardware measurement or latest-standard claim.
- The support-status example is scoped to Oracle's 2011 T10000 manual; the T10 proposal is not an approved standard. No device experiment was performed.