Quantum DLT 2500, Product Manual

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DLT2000 SCSI Interface
8-104 DLT2000/DLT2700 Cartridge Tape Subsystem
Sense Key
In most cases, Additional Sense Code and/or Qualifier information is available. See the
tables later in this section.
Information Bytes
These bytes contain the differences (residue) of the requested length minus the actual
length in bytes, blocks, or Filemarks, as determined by the command. Negative values
are indicated by two's complement notation. The bytes are valid for all read, write,
space, and verify tape commands for which a CHECK CONDITION status has been
generated. The information bytes are zero for MODE SELECT/SENSE, INQUIRY,
READ BLOCK LIMITS, and TEST UNIT READY.
Additional Sense Length
This specifies the number of additional sense bytes to follow. If the Allocation Length
of the command descriptor block is too small to transfer all of the additional sense
bytes, the Additional Sense Length is not adjusted to reflect the truncation.
Command Specific Information Bytes
Command Specific Bytes are handled as device specific and can be logged by the
operating system on error conditions. On media errors, this usually contains the current
SCSI Logical Block Address.
Additional Sense Code (ASC) and ASC Qualifier
These two bytes provide additional information about the Sense Key and cause of the
CHECK CONDITION status. See the tables later in this section.
Sub-Assembly Code
Unused at present, returned as 0.
Field Pointer Bytes
C/D - When set, indicates that the illegal parameter is in the CDB. A C/D of zero
indicates that the illegal parameter is in the Parameter List from the initiator.
BPV - When the Bit Pointer Valid bit is set, it indicates that the Bit Pointer field is
valid and designates which bit of the byte designated by the field pointer is in error. For
a multi-bit field, it points to the most significant bit of the field.
Field Pointer - Indicates which byte of the CDB or Parameter List was in error. For a
multi-byte field, the most significant byte is indicated.
Internal Status Code
For a complete definition of Internal Status Code, see Appendix B.