LOAD/UNLOAD | 6.Command Specification |
When the drive receives the UNLOAD, the tape is rewound to BOM and ejected. The operator must reload the drive manually. If, however, the drive has previously received a PREVENT MEDIA REMOVAL (with prevent bit set) command, the tape is retained in the drive. A subsequent LOAD command will load and position the tape at BOP ZERO. If an UNLOAD was sent instead, the drive would return NOT READY and the tape would remain within the drive. In this case, the drive requires a PREVENT ALLOW MEDIA REMOVAL (with prevent bit clear) command before an UNLOAD will eject the tape.
Note: While the PREVENT MEDIA REMOVAL is in effect, the Front Panel EJECT button is completely disabled.
If the cassette is unloaded but has not been ejected from the drive because of moisture detection, then a subsequent UNLOAD will cause the tape to eject from the drive. All commands except INQUIRY, REQUEST SENSE and READ BLOCK LIMITS will return a CHECK CONDITION status with a HARDWARE ERROR sense key set. The tape may also be ejected via the Front Panel EJECT button.
If no cassette is in drive, both LOAD and UNLOAD will return a CHECK CONDITION status with NOT READY sense key set
The valid combinations of the last four fields are given in Table
Table 6-4: LOAD UNLOAD Command Parameter Combinations
HOLD | RETEN | LOAD | ACTION |
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0 | 0 | 1 (Load) | Normal load to access the medium without a retension operation, positioned at BOP0. |
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| Logical unit in READY state. Immed may be ZERO or 1b. |
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1 | 0 | 1 (Load) | Load to access MAM only. logical unit in NOT READY state. Immed may be ZERO or 1b. |
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| MAM Load Count is not incremented. Unit Attention Condition set for MEDIUM AUXILIARY |
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| MEMORY ACCESSIBLE. |
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0 | 1 | 1 (Load) | Normal load to access the medium after a retension operation, positioned at BOP0. Logical |
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| unit in READY state. Immed may be ZERO or 1b. |
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1 | 1 | 1 (Load) | Invalid Combination. Command terminates with CHECK CONDITION Status. The sense key |
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| is set to ILLEGAL REQUEST and the ASC is set to INVALID FIELD IN CDB. |
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0 | 0 | 0 (Unload) | Normal Unload/Eject of cartridge. Logical unit enter NOT READY state. Immed may be |
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| ZERO or 1b. |
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1 | 0 | 0 (Unload) | Unload of cartridge, but MAM still accessible but cartridge is not ejected. Logical unit enters |
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| NOT READY state. Immed may be ZERO or 1b. Unit Attention Condition set for MEDIUM |
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| AUXILIARY MEMORY ACCESSIBLE. |
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0 | 1 | 0 (Unload) | Normal Unload/Eject of cartridge after a retension operation. Logical unit enters NOT READY |
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| state. Immed may be ZERO or 1b. |
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1 | 1 | 0 (Unload) | Unload of cartridge after retension operation, but MAM still accessible. Logical unit enter |
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| NOT READY state. Immed may be ZERO or 1b. |
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SONY |
