Hello.
sorry for my english.
i got big problem with "protect" my system.
i copied my win bootsector to sector no 3. in sector 1 i load my own bootsector witch ask for password. When password correct MBR load sector from 3 to the memory.

when i jmp to this location system fails. Example code:


mov ax,8000h
mov es,ax

mov ax,0201h
mov dh,1
mov dl,80h
mov cx,3
xor bx,bx
int 13h

jmp 8000h:0000h

hope someone help:)

looks like you're trying to read from the 1st head (mov dh, 1). heads and cylinders count from 0, only sectors count from 1.

yeh its something like this:

ORG 0x7C00


main:
mov ax,0x0000
mov ds,ax

mov ax,8000h
mov es,ax
mov ax,0201h
mov ch,0
mov cl,1
mov dh,0
mov dl,80h
xor bx,bx
int 13h


jmp 8000h:0000h



but still dosn't work.....

perhaps it's not disk 0x80? the BIOS loads DL with a code for the current boot disk. this code is specific to how many discs you have and their order.

plaster90,

Perhaps MBR you're loading expects to find itself somewhere around 0:7C00? Moreover, in your last example (can you use [code] tags?) you're trying to load sector from 0/0/1.