How to Read / Write sector on physical hardisk in Linux?

I want to read/write sector on Physical Hard Disk in Linux.

In MS-DOS, it can do by call Interupt (C language):
 asm {
    mov ah,0x41
    mov bx,0x55aa
    mov dl,DISK
    int 0x13
    mov r,ah
  }

In Windows, I already done.

But In linux, How to do this?

Thanks!