Once a SCSI device driver has been started, it must process I/O requests for the I/O abstraction that was installed in Driver Binding
Start(). In the case of the SCSI Disk Driver, these I/O abstractions are the Block I/O Protocol, the Block I/O 2 Protocol, and optionally the Storage Security Command Protocol. The Block I/O Protocols use the SCSI I/O Protocol to build SCSI command to perform operations to detect drive capabilities, read sectors, and write sectors. The EDK II
MdePkg also provide the library called
UefiScsiLib that provides functions to simplify the use of the SCSI I/O Protocol.