On the boot loader:

mov ax, 9ch
mov ss, ax
mov sp, 4096d
mov ax, 7c0h
mov ds, ax
;-------------------------------
times 510-($-$$) db 0
de 0xAA55

How do you give more bytes to the OS. When I change 510 too 600 it will compile and write 602 bytes. But when I load up the OS on virtual box it would get errors because the size is missing. Please help

Ok SkiMask11,

you cant add more bytes as 512 to the Master Boot Recosd (MBR).
you have to make a bootloader what boot your program and load it to the memory.

here some sites what explain:
http://wiki.osdev.org/MBR_%28x86%29
http://wiki.osdev.org/Bootloader

check out the site osdev.org to learn how to build a own Operating System.

Thank you