Sony SDX-1100V/R User Manual page 118

6.Command Specification READ
the media will be physically positioned before EOD and after the last block on tape.
The meaning of EOM is different for READ than for a WRITE type of command. EOM is only reported when the
physical EOM/P is encountered. The drive returns a CHECK CONDITION status. The EOM and Valid bits are set
and the Information field contains the residue count. If EOD is not written after the physical EOM/P, the Sense Key
is set to MEDIUM ERROR and the Additional Sense Code and Additional Sense Code Qualifier fields are set to
EOM/P Detected. If EOD is written, the Sense Key is set to BLANK CHECK and the Additional Sense Code and
Additional Sense Code Qualifier fields are set to EOD DETECTED. The tape is physically positioned at EOM/P.
For a Filemark, a (reported) Save-Setmark, EOD or EOM detected, if the Fixed bit is set, the Information field in
the REQUEST SENSE Data will be set to the difference (residue) between the requested Transfer Length and the
actual number of blocks read (not including the Filemark or Save-Setmark). If the Fixed bit is set to ZERO,
theIInformation field will be set the requested Transfer Length because Filemarks and Save-Setmarks are
considered to have a byte count of ZERO, (though this does not cause the ILI bit to be set).
The READ command may return the following sense keys on a CHECK CONDITION:
NO SENSE: If the actual Block Length is different from the specified Transfer Length and the SILI bit is ZERO, the
ILI (Incorrect Length Indicator) bit and Valid bit are set to one. The Information field in the Sense Data is set to the
difference (residue) between the requested Transfer Length and the actual Block Length, or in Fixed Block mode,
the difference (residue) between the requested number of blocks and the actual number of blocks read (not
including the incorrect length block). No more than Transfer Length bytes are transferred to the initiator and the
tape is logically positioned after the block (EOM side).
If the drive reads a Filemark during this command, it sets the Filemark bit in the REQUEST SENSE data. Upon
termination, the tape is logically positioned after the Filemark (EOM side). If, however, the drive encounters a
Save-Setmark during this command, nothing is reported unless the SDX-1100V has been configured through
MODE SELECT to Report Save Setmarks. If the Report Save Setmarks configuration is enabled then the Valid bit
and the Additional Sense Key flags are set in the REQUEST SENSE data to indicate that a Save-Setmark has
been encountered. The tape is also logically positioned after the Save-Setmark (EOM side).
For both a Filemark and a reported Save-Setmark, if the Fixed bit is one, the Information field in the REQUEST
SENSE data is set to the difference residue between the requested Transfer Length and the actual number of
blocks read (not including the Filemark or Save-Setmark).
If the Fixed bit is set to ZERO, the Information field is set to the difference (residue) between the requested
Transfer Length and the actual number of bytes read. Filemarks and Save-Setmarks are considered to have a
byte count of ZERO, though this does not cause the ILI bit to be set.
MEDIUM ERROR: The current block being read or a previously acknowledged WRITE type of operation
experienced an error probably related to the condition of the tape.
HARDWARE ERROR: Either a previously acknowledged WRITE type of operation had a major non-media related
failure or the read itself experienced the failure. The Valid bit is set, and the Information field contains the
appropriate residue. The meaning of EOM is different in a READ command from that in a WRITE type of
command. EOM is only reported on physical end-of-media. However, this condition is indistinguishable from other
fatal servo errors and so is reported as a HARDWARE ERROR.
BLANK CHECK: If EOD (End-of-Data) was encountered during a read, the sense key is BLANK CHECK, the
Valid bit is set and the Information field contains the residue count.
6-64 SONY AIT-5 drive SDX-1100V series Ver.1.0