This HowTo will use Debian GNU/Linux as the development platform inside a virtual machine on Windows with VirtualBox. Users of other OSes should be able to distinguish between VirtualBox and Windows to filter the information they really need.

To set up the development system, download Debian (here 5.0). Only DVD #1 is needed. Install it inside a virtual machine (VM) of VirtualBox.

• In the VM creation assistant choose…
  • Linux, Debian.
  • Memory should be at least 768MB RAM. More depending on the physical memory available.
  • Virtual hard disk should be 60GB, minimum is 35GB. 10GB for the OS. 5GB for OpenWrt package downloads. 20GB for each OpenWrt instance, as a lot of space is needed for all packages. Typical are two instances, one for trunk and one for release.
• If a personal firewall is used, make sure that VirtualBox can access the internet and act as a server for the trusted zone (LAN). Permanently or temporary as preferred. This is necessary to install the latest updates and to access the VM via SSH later.
• Set the boot options to only boot from harddisk.
• Assign the Debian DVD image to the VM's CD/DVD-ROM drive.
• For installation start the VM, hit F12 to access the boot menu and choose CD-ROM.

During the Debian installation…

• Choose English as the system's language, as it is best for international projects (e.g. bug reports, etc.).
• Choose correct country (e.g. via others) and keyboard layout (keymap).
• Please select a nearby network mirror near (for the latest updates).
• Only the standard system is needed. No desktop environment, etc. (maybe installed it if wanted).

Otherwise all the defaults are ok.

After Debian installed…

• Login as the root user (=Super-Admin in Linux/Unix)
• Mount the DVD-ROM image again, check if it got mounted, maybe /etc/fstab has to be corrected (/dev/hdc could be wrong) and if wished can later be unmounted

mount /dev/hdc     # hdc could also be hdb, look via "ls -la /dev/hd* | grep cd"
ls /cdrom

nano /etc/fstab

umount /cdrom

• Refresh the package list, install OpenSSH server and poweroff the virtual machine

aptitude update
aptitude install openssh-server
poweroff

• Add access to the SSH port of the Debian virtual machine in VirtualBox (see manual chapter 6.3.1 and chapter 8)

cd /d "%ProgramFiles%\Oracle\VirtualBox"
vboxmanage modifyvm "<VM name>" --natpf1 "guestssh,tcp,,22,,22"

Start the Debian virtual machine again. You should now be able to login via SSH (e.g via Putty or WinSCP) from the host system to the virtual machine (localhost:22).

Look at buildroot.exigence.