M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS
April 1997 CG00000-011503 REV. A 4-65
* Both fixed block and variable block modes are implemented by this tape controller. Reference the Read Block
Limits and Mode Select (mode parameters block descriptor) commands for more information about fixed and vari-
able block modes.
Encountering early-warning (LEOT) on a READ command is not reported to the initiator.
If a filemark is encountered during a READ command, the target returns CHECK
CONDITION status and sets the sense key to NO SENSE. The filemark and valid bits
are both set to one.
1If the Fixed bit is one, the target sets the information bytes to the difference (resi-
due) of the requested transfer count minus the actual number of blocks read (not
including the filemark).
0 If the Fixed bit is zero, the target sets the information bytes to the requested trans-
fer length.
The logical position is located after the filemark (EOM side).
If end-of-data is encountered during a READ command the target returns CHECK
CONDITION status, sets the sense key to BLANK CHECK, and sets the valid bit to
one.
1If the Fixed bit is one, the target sets the information bytes to the difference (resi-
due) of the requested transfer count minus the actual number of blocks read.
0 If the Fixed bit is zero, the target sets the information bytes to the requested trans-
fer length.
The logical position is located after the EOD block (EOM side). Subsequent Read
commands issued after EOD has been encountered and reported to the initiator will
result in reading into invalid/old data.
If a logical unit encounters the physical EOM during a READ command, the target
returns CHECK CONDITION status to the initiator and sets the End-Of-Medium
(EOM) bit to one in extended sense. The sense key is set to MEDIUM ERROR.
1 If the Fixed bit is one, the target sets the valid bit to one and the information bytes
to the difference (residue) of the requested transfer length minus the actual num-
ber of blocks successfully read.
0If the Fixed bit is zero the target sets the valid bit to one and the information bytes
to the requested transfer length.
FIXED
BIT SILI
BIT BLOCK
MODE * DESCRIPTION