WRITE 6.Command
Specification
SONY AIT-3Ex drive SDX-800V series Ver.1.0
6-105
6.29.
WRITE 0Ah
Bit
Byte
7 6 5 4 3 2 1 0
0
Operation Code (0Ah)
1
Obsolete Reserve
Fixed
2
(MSB)
3
Transfer
Length
4
(LSB)
5
Control
WRITE transfers one or more blocks from the Host to the tape beginning at the current logical position.
Fixed:
The Fixed Bit specifies both the meaning of the Transfer Length field and whether fixed-length or
variable-length blocks are to be transferred.
If the Fixed bit is set to ZERO, Variable Block mode is selected. The Transfer Length specifies the maximum number
of bytes that the drive handshakes out from the initiator. A single block is transferred from the initiator and is written
beginning at the current logical tape position. Upon successful termination, the tape is logically positioned after this
block (EOM/P side). The Transfer Length specifies the maximum number of bytes that the drive handshakes out
from the initiator.
If the Fixed Bit is set to one, the Transfer Length field specifies the number of blocks to be transferred to the drive,
beginning at the current logical position. This is valid only if the drive is currently operating in Fixed Block mode, in
other words, when it has been instructed to use fixed-length blocks with MODE SELECT. The current block length is
the block length defined in the MODE SELECT command. Upon termination, the tape is logically positioned after
these blocks (EOM/P side).
If EOT is detected while writing, the drive will finish writing any buffered data. The command will terminate with
CHECK CONDITION status. Within the Sense data, the EOM bit is set, the Sense Key field is set to NO SENSE and
the Additional Sense Code and Additional Sense Code Qualifier fields are set to EOM/P detected. The drive will
attempt to complete any subsequent writes, returning a CHECK CONDITION status in each case.
Note:
If the host issue a write command with the odd block size and Wide SCSI, the CHECK CONDITION STATUS
will be reached and the sense key will be set to ILLEGAL REQUEST.
If the drive encounters the physical EOM when attempting a WRITE, a CHECK CONDITION status is returned.
Within the Sense data, the EOM and Valid bits are set and the Sense Key field is set to VOLUME OVERFLOW. The
Information fields contain the residue count and the Additional Sense Code and Additional Sense Code Qualifier
fields are set to EOM/P Detected. The tape is physically positioned at EOM/P.
If the Transfer Length is ZERO, no data will be transferred and the current position on the logical unit will not be
changed.
The drive flushes its write buffer to tape and appends an EOD marker under the following conditions:
1.
Receipt of the following non-write commands:
READ
SPACE
ERASE
READ BUFFER
WRITE BUFFER
REWIND
LOAD/UNLOAD
MODE SELECT
LOCATE
The buffer can be maintained through the following media commands, assuming that no other flush condition has
been met, for example, write hold-off time-out.
WRITE
WRITE FILE MARKS with Immediate bit set
2.
The write hold-off time limit is exceeded.
