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How to make a Bochs disk image

First, use a real machine to setup a partition to your liking. If you need to tar up the disk, use something like:
```
tar czlp --same-owner -f c.img.tgz --exclude /tmp /
```
I exclude certain directories to save space.

Use the bximage tool that comes with Bochs to create a disk image:

bximage: hd, flat, 1500, c.img
 cyl=3047
  heads=16
  sectors per track=63
  total sectors=3071376
  total size=1499.70 megabytes

Use fdisk to create a partition table on the image file:
```
fdisk c.img
```
1. Setup geometry:
  - x - extra functionality
  - h 16
  - s 63
  - c 3047
  - r - return to main menu
2. n, p, 1, enter, enter - create new partition
3. a 1 - make bootable (optional?)
4. w - write the table to disk
Setup the loopback device -- note that you need to use an offset corresponding to the location of the first partition (explanation).
```
/sbin/losetup -o 32256 /dev/loop0 c.img
```
Format the disk:
```
/sbin/mke2fs -j /dev/loop0
```

Mount the disk to put files on it

mount /dev/loop0 /mnt
cd /mnt
tar xzvpf /home/bits7/NOBACKUP/kbarr/hpldisk/c.img.tgz

Now you need a bootloader. The /boot/grub/menu.lst on the image needs to be set up (presumably you did this in step 1). You'll need at least grub 0.95 as explained in this thread

% ./grub-0.95/grub/grub --no-floppy

grub> device (hd0) c.img

grub> geometry (hd0) 3047 16 63
drive 0x80: C/H/S = 3047/16/63, The number of sectors = 3071376, c.img
   Partition num: 0,  Filesystem type is ext2fs, partition type 0x83

grub> root (hd0,0)
 Filesystem type is ext2fs, partition type 0x83

grub> setup (hd0)
 Checking if "/boot/grub/stage1" exists... yes
 Checking if "/boot/grub/stage2" exists... yes
 Checking if "/boot/grub/e2fs_stage1_5" exists... yes
 Running "embed /boot/grub/e2fs_stage1_5 (hd0)"...  22 sectors are embedded.
succeeded
 Running "install /boot/grub/stage1 (hd0) (hd0)1+22 p (hd0,0)/boot/grub/stage2 /boot/grub/menu.lst"..
. succeeded
Done.

Make sure grub on the image is also 0.95. Also there may be problems if you try to use the graphical bootloader, so make sure you have the text-based one selected on the image's /boot/grub/menu.lst.

Offsets and loopback mounting

To determine the correct offset for mounting your disk image, do:

/sbin/sfdisk debian-3.0r0.img

You'll get a chart like:

Units = cylinders of 516096 bytes, blocks of 1024 bytes, counting from 0

   Device         Boot Start     End   #cyls   #blocks   Id  System
debian-3.0r0.img1          0+    260     261-   131512+  82  Linux swap
debian-3.0r0.img2        261    1023     763    384552   83  Linux

Take the starting cylinder that you care about (261). sfdisk is using cylinders of 516096 bytes, so the offset is 261*516096 = 134701056. Or, use fdisk (with -u) instead:

/sbin/fdisk -l -u c.img

In this case

Disk c.img: 0 heads, 0 sectors, 0 cylinders
Units = sectors of 1 * 512 bytes

Device Boot    Start       End    Blocks   Id  System
c.img1            63   1596671    798304+  83  Linux

And we take 63 * 512 = 32256.

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How to make a Bochs disk image

Offsets and loopback mounting