Building a PC Disk Image

Overview

The tools directory contains a set of bash scripts for automating the process of creating a hosted environment, a kernel for the PC, and images for floppy and hard disks. In this document we will create a hard disk image. This is a five stage process:

1. Create a hosted environment containing the files to include in the disk image.
2. Create an empty hard disk image.
3. Build a kernel to run from floppy disk which will be used to format the hard disk image - we will run this in qemu.
4. Build a kernel to run from the hard disk and install it in the FAT subpartition.
5. Copy the files from the hosted environment into the kfs subpartition.

We use the make-install-root.sh and make-disk.sh scripts to do this, as described below.

Running the scripts

Assuming you are starting from scratch, create a new directory and go into it.

Fetch the Inferno distribution into the inferno-os directory and the contents of this Wiki into the inferno-wiki directory:

#!bash

hg clone https://bitbucket.org/inferno-os/inferno-os
hg clone https://bitbucket.org/dboddie/inferno-os/wiki inferno-wiki

We create a hosted environment based on the contents of the inferno-os directory and use dd to create a hard disk image. 256M is a reasonable size to start with:

#!bash

./inferno-wiki/tools/make-install-root.sh inferno-os hosted
dd if=/dev/zero of=disk.img bs=1M count=256

It should now be possible to run the make-disk.sh script. This runs various other scripts from the inferno-wiki/tools directory to perform the steps described above. It will automatically run qemu to format the hard disk image, so be aware that a window will pop up when this happens.

#!bash

./inferno-wiki/tools/make-disk.sh inferno-os hosted disk.img

If it finishes successfully, it should print a message informing you that you can run qemu or qemu-system-i386 to test it in the following way:

#!bash

qemu -m 512M -drive file=disk.img -net user -net nic,model=rtl8139
qemu-system-i386 -m 512M -drive file=disk.img -net user -net nic,model=rtl8139

Hopefully, this should boot successfully to a console prompt after obtaining an IP address and binding directories in the kfs subpartition into the root filing system.

Testing the network connection

We can test whether the system running in qemu is connected to the network by running a command to fetch the main page of the Inferno site:

#!bash
dial -A tcp!www.inferno-os.org!80 { echo 'GET /'; cat >[1=2] }

This should return the HTML of the main page.