INT 13 - IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911./MS INT 13 Extensions - EXTENDED READ AH = 42h DL = drive number DS:SI -> disk address packet (see #00272) Return: CF clear if successful AH = 00h CF set on error AH = error code (see #00234) disk address packet's block count field set to number of blocks successfully transferred SeeAlso: AH=02h,AH=41h"INT 13 Ext",AH=43h"INT 13 Ext" Format of disk address packet: Offset Size Description (Table 00272) 00h BYTE size of packet (10h or 18h) 01h BYTE reserved (0) 02h WORD number of blocks to transfer (max 007Fh for Phoenix EDD) 04h DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. -> transfer buffer 08h QWORD(quad-word) Eight bytes. See also DWORD, PWORD. starting absolute block number (for non-LBA devices, compute as (CylinderThe set of concentric tracks of data located at the same position on each data-bearing surface of the disk. A double-sided floppy will contain two tracks per cylinder.*NumHeads + SelectedHead) * SectorPerTrack + SelectedSector - 1 10h QWORD(quad-word) Eight bytes. See also DWORD, PWORD. (EDD-3.0, optional) 64-bit flat address of transfer buffer; used if DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. at 04h is FFFFh:FFFFh