Fujitsu M2488 manual Write Filemark Command Operations, Write Filemarks Check Condition Status

M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS

Table 4-133. WRITE FILEMARK Command Operations

BUFFER	IMMED	OPERATION
MODE *	BIT
0h (non-buffered	0	Write requested filemarks to tape
mode)
	1	Illegal (ILLEGAL REQUEST) sense data will be presented
1h, 2h (buffered	0	Buffer new filemarks for write and then write all previously buffered data and
modes		filemarks to tape.
	1	Buffer 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

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:

BUFFER	BLOCK	INFORMATION FIELD
MODE	MODE
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.

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.

April 1997 CG00000-011503 REV. A 4-151