Sony DDS-4 Product Description Manual page 107

6. COMMAND SPECIFICATION
If the drive reads a Filemark, the drive will return a CHECK CONDITION status. Within the Sense data, the Filemark
and Valid bits are set and the Sense Key field is set to NO SENSE. The information fields contain the residue count. The
Additional Sense Code and Additional Sense Code Qualifier fields are set to Filemark Detected. Upon termination, the
media will be logically positioned after the Filemark (EOM side).
If, however, the drive encounters a Save-Set Mark during a READ, nothing is reported unless the drive has been config-
ured through MODE SELECT to Report Save-Set Marks. The drive will ignore the Setmark and continue the READ. If
the Report Save-Set Marks configuration is enabled then the Filemark and Valid bits are set and the Sense Key field is
set to NO SENSE. The information fields contain the residue count and the Additional Sense Code and Additional
Sense Code Qualifier fields are set to Setmark Detected. The tape is logically positioned after the Save-Set Mark (EOM
side).
If the drive detects EOD during the READ, the drive will return a CHECK CONDITION status. Within the Sense data,
the Valid bit is set and the Sense Key field is set to BLANK CHECK. The information fields contain the residue count.
The Additional Sense Code and Additional Sense Code Qualifier fields are set to EOD DETECTED. Upon termination,
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 fields contain 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 De-
tected. 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 END-OF-DATA DETECTED. The tape is physically positioned at EOM/P.
For a Filemark, a (reported) Save-Set Mark, 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-Set Mark). If the Fixed bit is set to zero, the information
bytes will be set the requested Transfer Length because Filemarks and Save-Set Marks are considered to have a byte
count of zero, (though this does not cause the ILI bit to be set).
READ 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 bytes in extended sense are set to the difference
(residue) between the requested Transfer Length and the actual Block Length, or in blocked 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-Set Mark during this command, nothing is reported unless the SDT-10000/SDT-11000 has been configured
through MODE SELECT to Report Save Set Marks. If the Report Save Set Marks 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-Set Mark
has been encountered. The tape is also logically positioned after the Save-Set Mark (EOM side).
For both a Filemark and a reported Save-Set Mark, if the Fixed bit is one, the Information bytes in the REQUEST
SENSE data are set to the difference residue between the requested Transfer Length and the actual number of blocks
read (not including the Filemark or Save-Set Mark).
6 - 56 SONY SDT-10000/SDT-11000 DDS Tape Drive
READ