Int 13/AH=4Ah

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Bootable CD-ROM - INITIATE DISK EMULATION

AH = 4Ah
AL = 00h
DS:SI -> specification packet (see #00281)

Return:
CF clear if successful CF set on error (drive will not be in emulation mode) AX = return codes

See Also: AH=48h - AX=4B00h - AH=4Ch - AH=4Dh

Format of Bootable CD-ROM Specification Packet: Offset Size Description (Table 00281) 00h BYTE size of packet in bytes (13h) 01h BYTE boot media type (see #00282) 02h BYTE drive number 00h floppy image 80h bootable hard disk 81h-FFh nonbootable or no emulation 03h BYTE CD-ROM controller number 04h DWORD Logical Block Address of disk image to emulate 08h WORD device specification (see also #00282)

(IDE) bit 0:
Drive is slave instead of master

(SCSI) bits 7-0:
LUN and PUN

bits 15-8:
Bus number 0Ah WORD segment of 3K buffer for caching CD-ROM reads 0Ch WORD load segment for initial boot image if 0000h, load at segment 07C0h 0Eh WORD number of 512-byte virtual sectors to load (only valid for AH=4Ch) 10h BYTE low byte of cylinder count (for INT 13/AH=08h) 11h BYTE sector count, high bits of cylinder count (for INT 13/AH=08h) 12h BYTE head count (for INT 13/AH=08h)

See Also: #00283 - AH=08h

Bitfields for Bootable CD-ROM boot media type: Bit(s) Description (Table 00282) 3-0 media type. 0000 no emulation. 0001 1.2M diskette. 0010 1.44M diskette. 0011 2.88M diskette. 0100 hard disk (drive C:). Other reserved 5-4 reserved (0) 6 image contains ATAPI driver 7 image contains SCSI driver(s)

See Also: #00281

Category: Disk I/O Enhancements - Int 13h - B

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