
SATA Transport Layer 253
queuing of the commands, the device returns a Register – Device to Host FIS, which clears the BSY bit
in the host, thus allowing it to send another command.
Command 5 Executes
In Figure 4.2, the device reorders the two commands based on Rotational Positional Ordering and
determines that the command with the TAG of 5 should be executed first. The device initiates the
command by issuing a DMA Setup FIS to the Host. When the host receives the DMA Setup FIS, it
determines the TAG value and activates the DMA control logic, which in turn programs the proper
Data Pointers. Now the First-party DMA transfer can commence. The De ...