Communication between SCSI Devices

When two SCSI devices communicate, one assumes the initiator-mode role, and the other assumes the target-mode role.

The initiator-mode device generates the SCSI command, which requests an operation, and the target-mode device receives the SCSI command and acts. It is possible for a SCSI device to perform both roles simultaneously.

When writing a new SCSI adapter device driver, the writer must know which mode or modes must be supported to meet the requirements of the SCSI adapter and any interfaced SCSI device drivers. When a SCSI adapter device driver is added so that a new SCSI adapter works with all existing SCSI device drivers, both initiator-mode and target-mode must be supported in the SCSI adapter device driver.