Linux on Windows? Try coLinux

Running a disk-based Linux like Knoppix (Home Page, Wikipedia) or complex virtualization solutions are not your only options for running Linux on a computer with Microsoft Windows.

coLinux (Cooperative Linux, Wikipedia) is not a Linux distribution: it's software that acts as a wrapper around Linux allowing it to run under the host operating (Microsoft Windows) as a native Windows application, negotiating resources for Linux from Windows. Linux communicates to coLinux through special device drivers starting with the characters "co" (since it cannot access devices under Windows directly). For example, if Linux wants to use a DVD drive, it must request it through coLinux which then negotiates sharing it with Windows.

This is sometimes referred to as a "virtualization appliance".

Here's how to get started with Ubuntu and coLinux 0.7.1 on a Pentium-based computer.

1. Download and install coLinux from Source Forge (http://sourceforge.net/projects/colinux/files.
2. Download and install winpcap (Home Page, Wikipedia) network packet capture driver. You'll be prompted for this during the coLinux install. It is OK to install it even if you don't need it.
3. Download and unpack a disk image for a linux distribution in the colinux directory on Source forge (e.g. ubuntu at http://downloads.sourceforge.net/colinux/Ubuntu-6.06.1.ext3.1gb.bz2?modtime=1191438204&big_mirror=0.

   You can also download more than one Linux distribution and create different batch and configuration files for each one.

4. Create a batch file
   (Wikipedia) called ubuntu.bat in the coLinux directory, and put one command in it: colinux-daemon @ubuntu.conf. Make a short-cut to your desktop for easy access and give it a nice icon if you wish. You'll need to run the batch file to start coLinux.

You can choose whether or not you want the separate "FLTK" console window (with the drop-down menus). Include the option "-t nt" if you want to use the batch file window: you save yourself an extra open window but lose the menus.

Make a copy of the example configuration file, example.conf, and name it ubuntu.conf and edit the settings in it to suit your computer.

Here's an example:

---

#
# This is an example for a configuration file that can
# be passed to colinux-daemon in this manner:
#
#    colinux-daemon @example.conf
#
# Note that you can still prepend or append configuration and
# boot parameters before and after '@', or you can use more
# that one '@ to load several settings one after another.
#
#    colinux-daemon @example.conf @overrider.conf mem=32
#
# Full list of config params is listed in colinux-daemon.txt.

# The default kernel
kernel=vmlinux

# File contains the root file system.
# Download and extract preconfigured file from SF "Images for 2.6".
# KB: This is essentially a ext3 disk image in a file format instead
# of a partition.  You can create similar disks and mount them with
# dd / mkfs.
cobd0="c:\Program Files\coLinux\Ubuntu-6.06.1.ext3.1gb"

# Swap device, should be an empty file with 128..512MB (e.g. created with dd)
# Add "mkswap /dev/cobd1; swapon /dev/cobd1" to rc.local
# KB: I used the one included with the Gentoo coLinux image.
cobd1="c:\Program Files\coLinux\Gentoo-colinux-i686-2007-03-03\gentoo\linux-swap"

# Tell kernel the name of root device (mostly /dev/cobd0,
# /dev/cobd/0 on Gentoo)
# This parameter will be forward to Linux kernel.
root=/dev/cobd0

# Make Windows C: drive available (within limits) under coLinux
# You'll have to mount it with coLinux.  e.g. make a /dosc and
# add to /etc/fstab:
# /dev/cofs0:Share      /mnt/windows            cofs    defaults          0 0
# Or mount manually with "mount -t cofs 0 /mnt/dosc"
cofs0=c:\

# Additional kernel parameters (ro = rootfs mount read only)
ro

# Initrd installs modules into the root file system.
# Need only on first boot.
initrd=initrd.gz

# Maximal physical memory for linux guest# Maximal physical memory for linux guest
#mem=64
mem=384

# Slirp for internet connection (outgoing)
# Inside running coLinux configure eth0 with this static settings:
# ipaddress 10.0.2.15   broadcast  10.0.2.255   netmask 255.255.255.0
# gateway   10.0.2.2    nameserver 10.0.2.3
# KB: slirp works out of the box but you can only see out, not in.
# Also, remember to configure resolv.conf.
eth0=slirp

# Tuntap as private network between guest and host on second linux device
#eth1=tuntap
# FORMAT: connection driver, ipconfig connection [, optional MAC address]
# eth0=pcap-bridge,"Loopback" - connect only to Windows XP
# KB instructions:
#   1. Rename the colinux tap network connection to Colinux Tap
#   2. Change "Local Area Connection" (or whatever connection is the real one)
#      to Advanced/Share.  Record IP (probably 192.168.0.1).
#   3. Enter that IP into the Colinux TAP TCP/IP setup. Ignore gateway/DNS
#      as real connection will take care of those.
# Still didn't get it to work.
#eth0=pcap-bridge,"Colinux TAP",,
eth1=pcap-bridge,"Local Area Connection",,

# Setup for serial device
#ttys0=COM1,"BAUD=115200 PARITY=n DATA=8 STOP=1 dtr=on rts=on"

# Run an application on colinux start (Sample Xming, a Xserver)
#exec0=C:\Programs\Xming\Xming.exe,":0 -clipboard -multiwindow -ac"

---

Alternatively, an xml-based configuration file can be loaded with "-c" but not all options are supported.

This is an explanation of some of the options:

1. Adjust how much memory will be taken from Windows on your computer for coLinux The default is 64 MB which is about the minimum to get Linux to boot. The maximum of 512 MB. Using too much will make Windows struggle; using too little will make Linux struggle. Remember that you can add swap space afterwards.
2. Make sure the root file image path (cobd0) is correct, pointing to the root Ubuntu image file you downloaded.

3. Create a swap file. Some Linux distributions for coLinux come with swap files included (I grabbed mine from Gen-Too when I tried it out). However, you can create your own with the Linux dd / mkswap commands (within coLinux or on another Linux machine). Put the Windows path to the swap file path in cobd1.
 

5. Start coLinux. If all is well, you should get a shell login prompt. The usual login/password is "root/root". Make sure your swap file is mounted by checking the available memory with Linux free command.

   If you see the message "Cannot open root device cobd0", check the path to cobd0 in the config file.

6. Networking

   Configuring networking for coLinux can be difficult because of the lack of current documentation and the reliance on third-party tools. There are three networking methods: slirp (runs "out of the box" but only allows you to connect out of coLinux, WinPTap (makes coLinux appear to be a separate computer on your network, but has limitations) and tuntap (makes coLinux visible to Windows on the same machine but not to other computes... http://vtun.sourceforge.net/tun/). It is possible to run these methods simultaneously through different network devices in coLinux (e.g. eth0 for slirp, eth1 for tuntap, etc.).

   The additional numbers on slirp enable port-forwarding from Windows TCP/IP ports to coLinux.

   Edit /etc/resolv.conf and add the nameservers. slirp (eth0) should work immediately.

   Get your IP number with ifconfig.

      # / Etc / hosts
      127.0.0.1 localhost
      192.168.0.190 colinux
   

   ping -c 1 ubuntu to make sure it works

      # The loopback interface
      auto lo iface lo inet loopback
      #
      # The first network card - this entry was created during the installation Debian
      # (network, broadcast and gateway are optional)
      auto eth0 iface eth0 inet static address 192.168.0.190 use the IP address of COLINU
   X netmask 255.255.255.0 gateway 192.168.0.210 use the gateway IP address
   

   Use ifconfig to make sure eth0 is up.

   Test with "ping -c 1 www.yahoo.com".

   The WinPTap or Tuntap methods are necessary if you want to connect to coLinux from the outside. For example, to log in with ssh or access the web server. eth1 talks to the host.

   I didn't get pcap working...perhaps because I'm not behind a router with IP masquerading (aka NAT).

   Install Microsoft's loopback driver through "add hardware" in the control panel (http://support.microsoft.com/kb/839013). Rename the new "Local Area Connection" to "Loopback". Assign the Loopback adaptor a static IP address. Don't use a "192.168.0" address.

7. C: Drive Access
   1. Create a mount partition (e.g. mkdir /dosc).
   2. Try mounting the C drive manually (mount -t cofs 0 /dosc) and ls /dosc to see if you can see the top directory of your C: drive. Unmount it with umount /dosc (note: not "unmount").
   3. Edit /etc/fstab and add the mount command listed above in the config file. mount /dosc. Did it mount?
 

8. Upgrading Packages

   Ubuntu is Debian-based so you need to use apt-get. Be aware that apt-get install kde will download all of kde and will be too big for the downloaded ubuntu file system unless you mount other file systems or some such. Also, it helps to know the package names before you start.

   apt-get update                  # (Ignore gpg errors)
   apt-get upgrade                 # Update existing packages

Periodically run these commands to keep your copy of Linux up-to-date.

To upgrade to the latest version of Ubuntu:

   apt-get dist-upgrade

The Ubuntu image is a minimal install. For development, you will want to install other software. For example:

   apt-get install man             # Linux Manual
   apt-get install nano            # pico-based editor
   apt-get install traceroute      # Network debugging tool
   apt-get install subversion      # Subversion source control
   apt-get install gcj             # GCC Java
   apt-get install gnat-3.3        # GCC Ada
   apt-get install lynx            # Console web browser

For LAMP (Linux/Apache/PHP) development:

   apt-get install php4            # PHP version 4 + Apache

For graphical development tools like kdevelop, you can include these:

   apt-get install xterm           # Basic X Windows
   apt-get install xfonts-base     # Standard fonts for drawing
   apt-get install xfonts-75dpi    # Standard fonts for drawing
   apt-get install kdebase         # Basic KDE
   apt-get install konsole         # KDE-enhanced xterm
   apt-get install kdevelop3       # KDevelop

For remote desktop access:

   apt-get install vncserver       # Virutal desktop
   vncserver -geometry 1024x768 -depth 8

You have a limited amount of disk space in your Ubuntu image file so you will not be able to install every available Ubuntu program. You can check your free disk space with df -h.

You can, of course, install the gnome desktop and anjuta IDE instead, or eclipse, etc.

9. X Windows

   coLinux cannot run X Windows applications directly because there are (currently) no drivers to make X draw inside of a Microsoft Windows' window. However, you can use an X system for Microsoft Windows as your display device. For example, the one that comes with the Cygwin system. Download and install Cygwin with X windows (that is, the basic X11 packages).

   There is also xming (http://www.sourceforge.net/projects/xming) X windows system for Microsoft Windows.

   With slirp, since you can only go "out" from coLinux, you'll need to manually configure Cygwin as your X windows display device.

   1. In Windows, get your IP number with ipconfig or your TCP/IP properties on your network connection.
   2. Start Cygwin
   3. In Cygwin, start xterm with startx.
   4. In Cygwin, xhost + to allow any connection.
   5. In coLinux, export DISPLAY="your ip:0"
   6. In coLinux, start xterm with xterm&. Did it work? Exit xterm with the exit command.

   If it works, add the DISPLAY variable to /etc/profile so that it runs automatically when you log in:

      DISPLAY="your ip:0" ; export DISPLAY

If you have the PTap configured, you should also be able to log into coLinux using "ssh -Y" from Cygwin and run kdevelop without having to modify xhost or DISPLAY (ssh handles all the configuration for you).

10. An Example Application: Kdevelop IDE

    With X Windows configured, you should be able to run most X Windows applications under coLinux, including kdevelop.

    In coLinux, start kdevelop with kdevelop3&. You should be able to access your Windows C: drive through the /dosc" mount point. You are now using kdevelop on Windows.

11. Logging out

    Shut down your virtual machine with shutdown -h now.

    Choose quit from the coLinux window menus. In NT mode, the console window will close automatically.

12. Mounting More Linux Drives

    cobd is "coLinux block device". That is, files that act as disk partitions. To create a new mountable "partition", create a file with enough space and format it for use.

    If you have your C: drive mounted under the /dosc mount point:

        dd if=/dev/zero of=/dosc/colinuxfs.dat bs=10M count=1
        # Create a 10 meg file
        # losetup is not used for a coLinux block device
        mkfs -t ext3 /dosc/colinuxfs.dat
        # You will be warned that it's not a partition (block device).
    

    Or, if your worried about Windows drive support or crashing, create the file on a Linux machine and copy it to your Windows drive.

    In the configuration file: cobd2="c:\colinuxfs.dat"

    Restart coLinux.

    Try mount /dev/cobd2 /mnt

    You can then mount it on startup in /etc/fstab, for example, as your home directory /home and share it between different versions of Linux running under coLinux. It will also free up some of your limited space under the root image file.

March 15, 2008