M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS
April 1997 CG00000-011503 REV. A 4-151
4-3.33.2 WRITE FILEMARKS CHECK CONDITION Status
If the Valid bit is set to 1 of Sense data for a CHECK CONDITION presented for a WRITE
FILEMARKS command then the Information field in the Sense data is set as follows:
When the WRITE FILEMARKS command is received, the tape unit tries to determine if there is a
reason why all of the requested filemarks can’t be written. The tape unit will check if the block IDs
for the requested filemarks are within the tape format limits. The tape unit may also check if the
requested number of filemarks will fit upon the remaining length of unwritten tape.
If the tape unit determines that the requested filemarks cannot all be written then it will not buffer
any of the filemarks and will present CHECK CONDITION status. The error sense data will indi-
cate VOLUME OVERFLOW, the Valid bit will be set to 1 and the Information field will be set as
described above. Note that if the tape unit does not present this type of error, it does not necessar-
ily mean that the requested filemarks will all fit on tape; the tape unit can only roughly estimate
how many filemarks will fit upon the remaining length of unwritten tape.
Table 4-133. WRITE FILEMARK Command Operations
BUFFER
MODE * IMMED
BIT OPERATION
0h (non-buffered
mode) 0Write requested filemarks to tape
1 Illegal (ILLEGAL REQUEST) sense data will be presented
1h, 2h (buffered
modes 0Buffer new filemarks for write and then write all previously buffered data and
filemarks to tape.
1Buffer new filemarks for write
* This is the Buffer Mode reported by the MODE SENSE command. It is contained in the device specific parameter
byte of the mode parameter header
BUFFER
MODE BLOCK
MODE INFORMATION FIELD
non-buffered Contains the number of new filemarks that were not
written.
buffered fixed Contains the number of buffered blocks and buffered
filemarks and new filemarks that were not written.
buffered variable Contains the number of buffered bytes and buffered
filemarks and new filemarks that were not written.