hesela.devSCSI TEST UNIT READY
SCSI TEST UNIT READY reports whether an addressed logical unit is ready for applicable operations without requesting a self-test.
Command: TEST UNIT READY uses opcode 00h. Its response concerns readiness, not the contents of a requested block range. Other conditions, including deferred errors, can yield BUSY or RESERVATION CONFLICT; a response is not limited to GOOD or CHECK CONDITION with sense key NOT READY. [1]
Interpretation: NOT READY can describe absent media or a logical unit becoming ready; it is not by itself a hardware-failure diagnosis. Read the status and returned sense together. [1]
Device scope: The cited tape-library interface reports readiness to accept commands and can return CHECK CONDITION for pending Unit Attention. A library response is not a readiness result for a tape drive or its loaded medium. [2]
Verification scope: The SIGMETRICS 2007 field study distinguishes media scrubs using drive-internal SCSI VERIFY from data scrubs that read sectors and compare stored checksums. These are sector-access mechanisms, not readiness probes; the study did not measure TUR detection sensitivity. [3]
Relations
- related
- SCSI, SCSI logical unit (LU), SCSI CHECK CONDITION, SCSI sense data, SCSI Unit Attention, Latent sector error, Data scrubbing
Limitations
- A successful readiness probe does not verify stored bytes, checksum integrity, write durability or the outcome of a later operation.