T13/2132-D Revision 3 June 23, 2010
60 Working Draft Enhanced Disk Drive - 4 (EDD-4)
Table 27 — CD Specification Packet
Offset Type Description
0 Byte 13h (e.g., Packet size in bytes)
1 Byte Boot Media Type
Bit Description
7 Emulated image requirements
Value Description
0b Emulated image is not driver dependent
1b Emulated image contains SCSI drivers for CD/DVD-ROM, bytes 8 and 9 refer
to a SCSI interface
6 Emulated image requirements
Value Description
0b Emulated image is not driver dependent
1b Emulated image contains ATAPI drivers for CD/DVD-ROM, bytes 8 and 9 refer
to an ATAPI interface
5:4 Reserved
3:0 Type of image to be booted
Value Emulation
0 No Emulation
1 1.2MB Diskette
21.44MB Diskette
32.88MB Diskette
4 Hard Disk
5-Fh Reserved
2 Byte INT 13h device number. This shall be the INT 13h number of the device which shall be started
or terminated. This value shall be zero for a floppy image, 80h for a bootable hard disk, and
81h through FFh for a non-bootable or no emulation device.
3 Byte Controller Index. This shall be the controller number of the to which the CD/DVD-ROM drive is
attached. If there are several controllers in a system, their number is system dependent.
4-7 DWord Logical Block Address of the disk image to be emulated. This shall be the abs olute sector
address of the image on the CD or DVD media.
8-9 Word Device Number. SCSI controllers shall use byte 8 as the Logical Unit Number (LUN) and byte
9 as the Physical Unit Number (PUN) of the CD or DVD drive. ATA/ATAPI controllers shall use
bit 0 of byte 8 to indicate device 0 or device 1.
10-11 Word User Buffer Segment. If this field is non-zero, the system may use a supplied buffer for
caching CD/DVD reads. This buffer shall be at least 3k in size. The buffer begins at
segment:0
12-13 Word Load Segment. This field is only used for booting (INT 13h FN 4Ch). If the value is zero, the
system shall use 7C0h as the load address and start address for booting. if the value is
non-zero, the system shall load the boot image at segment:0 and initiate the boot proce ss by
jumping to segment:0