Quantum 10K II - Manual (Page 82)

SCSI Description
Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives 5–15
5.6 Linked Commands
An I/O Process (task) may contain multiple commands that are linked together. The
initiator communicates this condition of linked (or unlinked) commands by setting
(or clearing) the Link bit of the Command Descriptor Block’s control word. A linked
command is one in which the Link bit in the Command Descriptor Block is set.
After successful completion of a linked command the drive sends an
INTERMEDIATE status, followed by a LINKED COMMAND COMPLETE message.
If the Flag bit was set in the Command Descriptor Block, the drive sends an
INTERMEDIATE status, followed by a LINKED COMMAND COMPLETE (WITH
FLAG) message. The drive then switches the bus to the command phase in order to
receive the next command in the linked chain.
All commands in a linked chain are addressed to the same nexus and are part of a
single task (I/O process). The drive defers any commands that are not part of the
linked chain until the chain is complete. The last command in the chain has the
Link bit cleared.
NOTE: Relative addressing is not supported by the Atlas 10K II disk drive.