SCS I Description
M axtor Atlas 10K III 5-9
An I/O Proc ess (t a sk) ma y contain multiple c ommands th a t ar e l inked together. The
initiator communicates this condition of linked (or unlinked) commands by setting (or
clearing) the Link bit of the Command Descriptor Block’s c ont ro l word . A li nked
command is one in which the Link bit in the Comm and Descriptor Block is set.
After successful completion of a linked com mand the drive sends an
INTERMEDIATE status, followe d by a LINKED COMMAND COMPLETE
mes sage. If th e Flag bit was set in the Command Descr iptor Block , t he drive sen ds an
INTERMEDIATE status, followe d by a LINKED COMMAND COMPLETE
(WITH FL A G) message. The drive then swit ches the bus to the comm and 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 comm and in the chain has the Link bit cleared.
Relative addressing is not supported by the Atlas 10K III disk
drive.