The OS/2 CD-ROM Device Manager (OS2CDROM.DMD) is a generic CD-ROM device driver for CD-ROM drives that comply with the ANSI SCSI-2 standard X3T9.2/86-109 (SCSI-2 draft proposed American National Standard Revision 10g). The device driver provides generic data and audio support for drives that support the command set specified in that standard. Vendor unique CD-ROM XA support and multi-session support is provided for selected drive models.
The CD-ROM Device Manager provides a uniform interface between its clients and adapter device drivers. Clients of the Device Manager include:
The CD-ROM File System communicates with the CD-ROM Device Manager using the request packet interface defined in the OS/2 Physical Device Driver Reference version 2.00 or later.
The Multimedia Presentation Manager/2 subsystem and OS/2 applications communicate with the CD-ROM Device Manager using the Category 80 and 81 IOCtl services defined in the OS/2 Physical Device Driver Reference.
DOS applications communicate with the CD-ROM Device Manager indirectly through the virtual DOS CD-ROM device driver VCDROM.SYS. VCDROM.SYS provides virtual support and converts the DOS application request into a file system or Cat 80/81 IOCTL request which is routed to the CD-ROM Device Manager using system device helper services.
The interface between the CD-ROM Device Manager and adapter device drivers adheres to the adapter device driver interface defined in earlier chapters of this reference. The CD-ROM Device Manager converts a request from its client into a SCSI-2 command descriptor block and routes the SCSI-2 command to the specified adapter device driver. The SCSI-2 commands are sent using the IORB adapter passthru command (command code = ADAPTER_PASSTHRU, command modifier = EXECUTE_CDB).
The CD-ROM Device Manager driver (OS2CDROM.DMD) is an installable block device driver and is loaded using a DEVICE= statement in CONFIG.SYS. The driver replaces CDROM.SYS, the CD-ROM device driver shipped in the OS/2 2.1 product.