Running an OS on VirtualBox

Question

I am using VirtualBox 4.1.14 on Windows 7 and I am trying to make it run my test OS. I am using the assembly code below and I am compiling it with

nasm -f bin -o boot.bin boot.asm

I am trying to convert the resulting bin file into an ISO that VB4.1.14 can use (I don't want to have to pay money or have any limits from a trial program). I have tried downloading different converters like bin2iso but VB comes up with different errors whenever I try to open the resulting ISO inside it like VERR_NOT_SUPPORTED and others.

I would prefer the solution to be a command line tool so I can use it in a batch script to make testing faster.

BITS 16

start:
    mov ax, 07C0h       ; Set up 4K stack space after this bootloader
    add ax, 288     ; (4096 + 512) / 16 bytes per paragraph
    mov ss, ax
    mov sp, 4096

    mov ax, 07C0h       ; Set data segment to where we're loaded
    mov ds, ax


    mov si, text_string ; Put string position into SI
    call print_string   ; Call our string-printing routine

    jmp $           ; Jump here - infinite loop!


    text_string db 'This is my cool new OS!', 0


print_string:           ; Routine: output string in SI to screen
    mov ah, 0Eh     ; int 10h 'print char' function

.repeat:
    lodsb           ; Get character from string
    cmp al, 0
    je .done        ; If char is zero, end of string
    int 10h         ; Otherwise, print it
    jmp .repeat

.done:
    ret


    times 510-($-$$) db 0   ; Pad remainder of boot sector with 0s
    dw 0xAA55       ; The standard PC boot signature

Answer 1

You can use dd (search dd for windows) to create a floppy for starters. The binary is just written to the first 256 bytes of a 1440 kib file.

dd if=/dev/zero of=floppy.img ibs=1k count=1440
dd if=boot.img of=floppy.img conv=notrunc

And here we go: