Fujitsu M2488 - page 224

TAPE UNIT SCSI COMMANDS M2488 PRODUCT GUIDE
4-142 CG00000-011503 REV. A April 1997
It is possible for the value in the information bytes of the sense data generated when a CHECK
CONDITION is returned for a WRITE command to exceed the transfer length specified in the
CDB of the WRITE command.
Early Warning Indication:
If a WRITE command is received while the logical unit is positioned after the early-warning indi-
cation (but before physical EOM), the target continues to operate in the current Buffered Mode as
indicated in the mode parameters (reference MODE SENSE/SELECT data header) using the
buffer size indicated by the Buffer Size at Early-Warning mode parameter (reference MODE
SENSE/SELECT page 10h). The target also returns a CHECK CONDITION status for each of
these WRITE commands. If all of the data is successfully transferred into the buffer and physical
EOM has not been encountered, the sense key is set to NO SENSE, the valid and EOM bits are set
to one, and the information bytes are set to zero. If physical EOM is encountered, the sense key is
set to VOLUME OVERFLOW, the EOM bit is set to one, the valid bit is set to one, and the value
of the information bytes are as described above.
Deferred Write Errors:
A deferred write error condition occurs when the target detects an error has occurred on a buffered
WRITE command that previously reported GOOD status. This condition persists until one of the
following occurs:
1) The deferred error is reported and the buffered data is recovered by the initiator via the
Recover Buffered Data command.
2) The deferred error is reported and the buffered data is discarded by the initiator via the Rewind
or Load/Unload command.
3) A BUS DEVICE RESET message is received from any initiator.
4) A hard reset condition is detected by the target.
If a deferred write error occurs while operating in Buffered Mode 1 (data from multiple initiators
can reside in the buffer at once), the deferred write error is reported to the first initiator issuing the
next command if other than INQUIRY or REQUEST SENSE. If a deferred write error occurs
while operating in Buffered Mode 2 (the buffer can contain data from only one initiator), the error
is reported to the initiator with unwritten data in the buffer. All other initiators receive BUSY sta-
tus until the deferred error condition is cleared.
Additional Information:
The target ensures that some additional data can be wr itten to the medium (e.g. filemarks) after the
first EOM indication has been returned to the initiator.
The data written to the tape is written in EDRC compressed format depending on the Select Data
Compression Algorithm field in the Mod e (SE NSE /SE L ECT ) par ame t ers, M ode Page 10h. See the
description of the Mode SENSE/SELECT parameters for more information on the compression
mode based on these items.
This device writes all data to tape in 36-track format. Therefor, if an attempt is made to write over
18-track data away from BOT, CHECK CONDITION status is generated. The sense key is set to
MEDIUM ERROR and the additional sense code is set to INCOMPATIBLE MEDIUM
INSTALLED.