Other / Unknown OS "No Bootable Medium Found"

Discussions about using non Windows and Linux guests such as FreeBSD, DOS, OS/2, OpenBSD, etc.
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CodeFlow
Posts: 2
Joined: 28. Jun 2020, 10:20

Other / Unknown OS "No Bootable Medium Found"

Post by CodeFlow »

I have made my own OS (a bit of it) And I try to launch it in virtualbox and it doesn't work,
Here's the code for the .asm (BEFORE PUT INTO ISO)
(BOOTLOADER)

hello_world.asm

Code: Select all

[bits 16]           ; tell assembler that working in real mode(16 bit mode)
[org 0x7c00]        ; organize from 0x7C00 memory location where BIOS will load us

start:              ; start label from where our code starts
	MOV AX,0600H    ;06 TO SCROLL & 00 FOR FULLJ SCREEN
    MOV BH,70H    ;ATTRIBUTE 7 FOR BACKGROUND AND 0 FOR FOREGROUND
    MOV CX,0000H    ;STARTING COORDINATES
    MOV DX,184FH    ;ENDING COORDINATES
    INT 10H        ;FOR VIDEO DISPLAY
    MOV AH,4CH    ;RETURN TO DOS MODE
    INT 21H
	
    xor ax,ax           ; set ax register to 0
    mov ds,ax           ; set data segment(ds) to 0
    mov es,ax           ; set extra segment(es) to 0
    mov bx,0x8000

    mov si, hello_world              ; point hello_world to source index
    call print_string                      ; call print different color string function
    hello_world db  'Loading.',13,0	;First Text


print_string:
    mov ah, 0x0E            ; value to tell interrupt handler that take value from al & print it

.repeat_next_char:
    lodsb                ; get character from string
    cmp al, 0                    ; cmp al with end of string
    je .done_print               ; if char is zero, end of string
    int 0x10                     ; otherwise, print it
    jmp .repeat_next_char        ; jmp to .repeat_next_char if not 0

.done_print:
    ret                         ;return

    times (510 - ($ - $$)) db 0x00     ;set 512 bytes for boot sector which are necessary
    dw 0xAA55                                                      ; boot signature 0xAA & 0x55
How can I fix?
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Other / Unknown OS "No Bootable Medium Found"

Post by mpack »

Why are you talking about ISOs? Isn't this a hard disk boot loader?

Where is the partition map?

What makes this a "Windows Hosts" question?
CodeFlow
Posts: 2
Joined: 28. Jun 2020, 10:20

Re: Other / Unknown OS "No Bootable Medium Found"

Post by CodeFlow »

Sorry i'm new to making os and the forums. what should i put it in as a boot loader?

and what is partition map
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Other / Unknown OS "No Bootable Medium Found"

Post by mpack »

Topic moved to "Other Guests".

Did you write the above code yourself? The knowledge required to write the first part of that code doesn't seem to square with someone who doesn't know what a partition map is, or a boot sector, or the difference between BIOS and DOS calls. The code seems to be taken from a DOS app of some kind, given that it includes a DOS call (int 21h Function 4Ch - Terminate App) - which will simply crash on a PC not running DOS. And even on DOS the app would terminate with that call, so the code following it is never reached.

Sorry, but your knowledge is way below what's needed to write an OS, or even to participate in a useful discussion about it. Everyone has to start learning somewhere, but I suggest you start with something achievable, such as an Arduino project of some kind.
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