Commands 155
Commands
CDB Fields:
Write Specific Status:
See also the “Additional Sense Codes” on page 136 for a variety of possible
hard errors.
An attempt to write to a write-protected cartridge will produce a
CHECK
CONDITION
with a sense key of DATA PROTECT and additional sense of 2700h
(write-protected).
An attempt to write to a cartridge whose Cartridge Memory has failed will
produce a
CHECK CONDITION with a sense key of MEDIUM ERROR and
additional sense of 3004h (cannot write medium). If, however, the tape is not
positioned at BOT, the drive will respond with sense data as if the tape is write-
protected. The WP flag in the Mode Parameter Header will also be set.
If EOM (end of medium) is encountered during a write,
CHECK CONDITION
status is reported. The EOM flag will be set. The sense key will be set to
VOLUME OVERFLOW with additional sense of 0002h (EOT). Residue
information will be as below. The logical position will be EOD.
Subsequent Request Sense commands will, however, give tape position as
EOP/M (end of partition/media). It may still be possible to write a smaller
quantity of information at this point (such as filemarks or a smaller block). This
is because logical position after failure to write a block returns to the start of
the unwritten block.
Early Warning EOM information is reported only if a write operation is
successful. This is done by reporting
CHECK CONDITION status with a sense
key of
NO SENSE and additional sense of 0002h (EOT). Residue information is
valid and indicates zero blocks/bytes.
Residue Information:
Residue information depends on two variables:
■ Fixed or Variable block mode.
Fixed 0 The Transfer Length field specifies the length of the transfer in bytes.
1 The Transfer Length field specifies the length of the transfer in blocks. The size of each
block (in bytes) is determined by the current Block Length given in the Mode Select
Parameter block descriptor.
Transfer Length 0 No data is transferred. The current logical position will be unchanged.
>0 The amount of data to be transferred, in bytes or blocks as determined by the Fixed field.
