Transferring data on the SCSI bus is managed by the host adapter . On modern host adapters ( since about 1997 ) , doing I\/O to the adapter sets the SCSI ID ; for example , the adapter often contains a BIOS program that runs when the computer boots up and that program has menus that let the operator choose the SCSI ID of the host adapter . Alternatively , the host adapter may come with software that must be installed on the host computer to configure the SCSI ID .