Write Command
August 2016 Commands 235
Notes:
1. Setting of the fixed bit is only allowed if the fixed block length is not zero. If block
length is 0, the drive is in variable block mode. In fixed block mode, the record
size is specified by the block length.
The Mode Sense command reports the block length.
2. The Buffered Mode field of the Mode Select command controls when status is
returned. If Buffered Mode is:
0 = Status is returned after all data is written on the tape.
1 = Status is returned after all data is in the buffer.
3. If the logical end-of-tape (LEOT) is encountered while writing on the tape, Check
Condition status is returned and the end-of-medium (EOM) bit is set in sense
data. The SEW bit in the mode sense device configuration page controls when
data is written to the tape at LEOT.
4. If the physical end-of-tape (PEOT) is encountered, Check Condition status is
returned and the sense key is set to Volume Overflow.
5. An un-correctable media error generates Check Condition status with a sense key
of Media Error. Unwritten buffered records or filemarks are trapped in the buffer by
this media error. Other tape motion commands are not allowed until the buffer is
intentionally cleared by a Rewind or Unload command.
6. If a Write command returns Check Condition status, the valid bit in the Request
Sense data is set.
7. The Request Sense information bytes are zeros if all data was written on tape. In
variable block mode, the data indicates the total number of bytes not written on
tape.
8. In fixed block mode, the information bytes return the total number of blocks not
written on tape. A filemark is counted as one byte or block.
9. In buffered mode this total may include records from previous Write or Write
Filemarks commands.
10. The error code is set to Deferred Error if records from other than this command
remain in the buffer.
Parameter Value
Fixed Indicates the block mode for data transfer:
0 = Variable block mode.
Transfer Length specifies the length of the block in bytes to be
written. A single block is transferred from the initiator.
1 = Fixed block mode.
Transfer Length specifies the number of blocks to be
transferred to the device.
Transfer Length Number of blocks or bytes requested
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