HI
I try read 3mb(6144 sector) from harddisk.
my harddisk support from INT 13h AH=42h: Extended Read Sectors From Drive

#-------part from site http://wiki.osdev.org/ATA_in_x86_Rea...29------------
DAPACK:
db 0x10
db 0
blkcnt: dw 16 ; int 13 resets this to # of blocks actually read/written
db_add: dw 0x7C00 ; memory buffer destination address (0:7c00)
dw 0 ; in memory page zero
d_lba: dd 1 ; put the lba to read in this spot
dd 0 ; more storage bytes only for big lba's ( > 4 bytes )

mov si, DAPACK ; address of "disk address packet"
mov ah, 0x42 ; AL is unused
mov dl, 0x80 ; drive number 0 (OR the drive # with 0x80)
int 0x13
jc short .error
#-----------------------------------
IF i change part of red with 6144 , i can read 3mb from harddisk?

No. In "real mode" you can't even address 3mb.

With some BIOS's you would be limited to 64KB. With other BIOS's you could transfer more than 64KB. I don't know how much more. But not more than the amount of ram you can address in "real mode". Under boot up conditions that would be at most 640KB.

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