Emulating the XO

Latest Release:
Stable: Build 406 (May 7)
LiveCD: ISO-Build 385 (Apr 7)

laptop-in-laptop

Quick Start

To set up a "virtual XO", and get a taste of the XO software, see Quick Start.

Context

One way to run oplc software is using an emulator on your pc. See Software and Getting started programming for other options.

Compared to using a developer image LiveCD, running XO disk images might be harder to set up, but easier to develop on. And compared to installing sugar, easier, but harder.

See Category:Emulation for related pages.

Alternatives

An OLPC laptop is custom hardware, running a stripped-down Red Hat linux, running Sugar. But what if you don't have a real olpc laptop? There are a several options.

option	note	updated	hardware?	library?	writable?	development software?	network?	comments
LiveCd		April	yes	no	no	toolchain, Gnome	yes	Alternative Quick Start. Good for new developers. Problems: A.
XO disk images:			no		yes
LATEST-STABLE-BUILD
...development.ext3.img		~monthly	no	yes	yes	no	extra step	Quick Start for getting a look at Sugar.
...development-devel.ext3.img		~monthly	no	no	yes	a little	extra step
LATEST
...development.ext3.img		~daily	no	yes	yes	no	extra step
...development-devel.ext3.img		~daily	no	no	yes	a little	extra step	Good for new developers (requires some command-line comfort).
FC6+Sugar		April	yes	yes?	yes	Full Fedora Softare Dev.	yes	6GB (April version: no etoys)
Installing Sugar		continuous	yes	yes	yes	your own	yes	Quite hard to do.

Notes:

hardware: Might your camera/video work. Is there even sound in the xo disk images?

library: The olpc default library is included (english version). Ie, pretty text to web browse without having to get network.

writable: With an .img, you can save things between sessions. With a .iso, your environment is the same each time you start.

development software: are development tools included?

network: does the network "just work"?

Problems:

A: LiveCd (April) on fc6 x86_64, kernel panics under kqemu.

Todo:

• Maybe add columns: etoys?

Future possibilities

It would be nice to have:

• a small (like LiveCd) livecd with library/. To be an "intro" livecd for non-developers to try sugar.

  Perhaps create a mutant LiveCd. Take LiveCd, unsquash its squashfs, add library, resquash, and mkisofs. Downsides: LiveCd isn't updated very frequently (but since an update is coming rsn, perhaps we don't care just now).

• a small (like LiveCd) qemu image with full fedora host detection/configuration (like Big FC6 Build). To be an "intro" qemu image for non-developers, and a sound&video-works (hopefully) image for developers.

  Perhaps derive from LiveCd? The bottleneck is getting a clean sugar-jhbuild. LiveCd is the only production source of this human intensive process, other than the latest-stable-builds, which are xo-specific. It's not clear that one could get from any xo disk image to a hardware-independent build. Perhaps one might find out what versions of things went into a latest-stable-build? Perhaps sugar-jhbuild works not-infrequently for some particular environment, eg fc7 x86? Perhaps take someone's fc6+sugar image (Big FC6 Build lacks etoys), attempt updating it, and strip it down?

  Re derive from LiveCd, one might be able to unsquash the fs, customize for this role, make a qemu image with it, and add boot stuff?

Emulation for Development

The most common approach is to use QEMU with kqemu acceleration. See Quick Start for the basics. But we will use a different .img, one with a few extra utility programs. See OS images. Including the latest stable build.

Instead of qemu, you can run VMware, and there are addition options on a Mac.

Emulating the XO/Help and tips may help. Please report your experiences in User Feedback on Images. There is a Virtualization Common Room.

There are limitations with XO disk images.

Development using QEMU

If you wish to develop software on an emulated image, you will usually want a connection between your host and the laptop image.

You need a "*-devel*.img" image, rather than a standard (non-devel) one. The -devel image has extra software like sshd and wget.

Get network working on the laptop. See Using QEMU for Troubleshooting#Network. A simple echo ifup eth0 >> /etc/rc.local , run as root on the laptop, should do it. You should now be able to surf with the laptop's web activity. Under QEMU the Laptop image can see the host as IP address 10.0.2.2 .

Next, you have several alternatives:

• SSH using qemu -redir tcp:2222::22. (a good first approach)
  1. First-time setup
     1. Get the image's network working.
     2. Change the image's root password.

        Log into the image as root (no password needed yet!), type passwd , and then give it one. Complaints about "BAD" passwords won't stop things from working.

        Logging in as root is easy in qemu - you have a console window. Elsewhere...(? someone else will need to fill this in)

  2. Whenever you run qemu, add the argument -redir tcp:2222::22
  3. You can now log into the laptop image, from your real machine, using ssh. And you can use scp, etc.

ssh -p 2222 root@localhost     # simple
ssh -o NoHostAuthenticationForLocalhost=yes -p 2222 root@localhost  #avoids annoying warning

• SSH using a key. (if ssh passwords get annoying, you can try this)

  If you create an SSH server on your host and install a key on your Laptop image that has logon rights for that server, you can ssh from the OLPC to your host. This avoids password typing.

  Adding platform-specific instructions might be useful? MitchellNCharity 15:59, 21 May 2007 (EDT)

• Using a web server. (if you don't want to deal with ssh, and have a webserver)

  If you have a web server, you might simply download stuff onto the laptop using the laptops's web browser.