Writing Device Drivers

SCSA Interface

SCSA is the Solaris 7 DDI/DKI programming interface for the transmission of SCSI commands from a target driver to a host adapter driver. By conforming to the SCSA, the target driver can pass any combination of SCSI commands and sequences to a target device without knowledge of the hardware implementation of the host adapter. SCSA conceptually separates the building of a SCSI command (by the target driver) from the transporting of the command to and data to and from the SCSI bus (by the HBA driver) for the appropriate target device. SCSA manages the connections between the target and HBA drivers through an HBA transport layer, as shown in Figure 14-1.

Figure 14-1 SCSA Interface