creating the floppy image and booting with bochs.

eXeCuTeR · **Joined:** Tue Dec 09, 2008 12:43 pm **Posts:** 63

I'm trying to create a floppy image in order to boot my kernel (and not used a pre-made floppy image!)
I've created a new directory named /mnt and a new image called floppy.img and did the following:

Code:

dd if=/dev/zero of=floppy.img bs=1024 count=1440
sudo /sbin/losetup /dev/loop0 floppy.img
sudo mkfs -t ext2 /dev/loop0
sudo mount -t ext2 /dev/loop0 /home/executer/Desktop/paging/mnt
sudo cp src/kernel /home/executer/Desktop/paging/mnt/kernel
cd mnt
sudo mkdir grub
sudo cp /usr/lib/grub/i386-pc/stage[12] /home/executer/Desktop/paging/mnt/grub
sudo grub --device-map=/dev/null
sudo umount /dev/loop0
sudo /sbin/losetup -d /dev/loop0
sudo bochs -f bochsrc.txt

bochsrc.txt is supposed to tell Bochs to load floppy.img,

Code:

megs: 32
romimage: file=/usr/share/bochs/BIOS-bochs-latest, address=0x00000
vgaromimage: /usr/share/bochs/VGABIOS-elpin-2.40
floppya: 1_44=floppy.img, status=inserted
boot: a
log: bochsout.txt
mouse: enabled=0
clock: sync=realtime
cpu: ips=500000

but apparently this is not working! Bochs tries to boot from floppy and then it says that there's no bootable device!
(i also tried qemu -fda floppy.img, and still it said "No bootable device.")
Please help out guys, thanks.
(I've gotta mention that i've created a grub directory in the mnt dir and put stage 1, stage 2 in it...and i also installed grub in /dev/loop0 this way:

Code:

grub --device-map=/dev/null
grub> device (fd0) /dev/loop0
grub>root (fd0)
// root(fd0) produced: Unknown partition table signature
grub> setup (fd0)
// setup(fd0) produced:
 Checking if "/boot/grub/stage1" exists... no
 Checking if "/grub/stage1" exists... yes
 Checking if "/grub/stage2" exists... yes
 Checking if "/grub/e2fs_stage1_5" exists... no
 Running "install /grub/stage1 (fd0) /grub/stage2 p /grub/menu.lst "... succeed
ed
Done.

)

Ztane · **Posted:** Fri Dec 19, 2008 4:55 pm

Ahem, so you have /dev/loop0 in your bochsrc? Bochs uses disk image files as is, so why not try replace that with floppy.img?

eXeCuTeR · **Joined:** Tue Dec 09, 2008 12:43 pm **Posts:** 63

Ztane wrote:

Ahem, so you have /dev/loop0 in your bochsrc? Bochs uses disk image files as is, so why not try replace that with floppy.img?

Yeah, floppy.img is in there, not /dev/loop0.

Hangin10 · **Joined:** Wed Feb 27, 2008 12:40 am **Posts:** 162

Once you have one floppy image with a filesystem containing /boot/grub/stage1&2, and one image that starts with stage1+2, perhaps use floppya for the bootable image, and floppyb for the filesystem one, and then boot bochs and go root (fd1) / setup (fd1), and you're good to go (along with my grammar apparently, that sentence was horrible! #-o

).

geppy · **Joined:** Wed Jun 11, 2008 5:30 pm **Posts:** 27

either Bochs can't find floppy.img or it can't find signature 0aa55h at the end of first 512bait of the floppy image (check with hex editor).

kasper · **Posted:** Tue Dec 23, 2008 2:18 am

Hi eXeCuTeR and others,

I use:

Code:

grub> install (fd0)/grub/stage1 (fd0) (fd0)/grub/stage2 (fd0)/grub/menu.lst

instead of the

Code:

Running "install /grub/stage1 (fd0) /grub/stage2 p /grub/menu.lst "... succeeded

that

Code:

grub> setup (fd0)

produces.

Until now I ran grub install from within bochs. Via an auxilary disk created with dd. But directly running grub on a loop device is easier. Thanks for this question.

Kasper

OSDev.org

creating the floppy image and booting with bochs.

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