Product manual

Barracuda 7200.7 Serial ATA Product Manual, Rev. C 3
The Serial ATA host adapter and drive share the function of emulating paral-
lel ATA device behavior to provide backward compatibility with existing host
systems and software. The Command and Control Block registers, PIO and
DMA data transfers, resets, and interrupts are all emulated.
The Serial ATA host adapter contains a set of registers that shadow the con-
tents of the traditional device registers, referred to as the Shadow Register
Block. All Serial ATA devices behave like Device 0 devices. For additional
information about how Serial ATA emulates parallel ATA, refer to the “Serial
ATA: High Speed Serialized AT Attachment” specification. The specification
can be downloaded from http://www.serialata.com.