Several leading CD-ROM drive manufacturers use a proprietary, non-SCSI, host adapter interface for the CD-ROM drive. To support a non-SCSI CD-ROM drive, an adapter device driver is required that emulates a SCSI-2 target device. This enables the CD-ROM Device Manager to issue a common command set to it's target devices, whether or not the firmware on the target device directly supports the SCSI-2 command set.

A non-SCSI CD-ROM adapter device driver adheres to the adapter device driver interface defined in DASD, SCSI, and CD-ROM Device Manager Interface Specification. It must support the ADAPTER_PASSTHRU command for EXECUTE_CDB requests, The SCSI-2 commands are sent from the CD-ROM Device Manager using this command.

The SCSI-2 commands must be emulated by the adapter device driver. This includes sense data which is returned back to the CD-ROM Device Manager.