Emulating the XO

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Revision as of 16:03, 6 July 2007 by 24.128.48.3 (Talk)
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Contents

Quick Start - LiveCD

For many, the LiveCD is the easiest way to try Sugar. It's easy to do, but your work is lost when you reboot.

Quick Start - Emulation

Emulation is the other way to try Sugar. It can be harder to set up,, but work is preserved.

Sound in TamTam may not be working at the moment. MitchellNCharity 13:16, 5 June 2007 (EDT)

Quick Start for Developers

Developing on emulation is one alternative for developing software.

Get the latest image from here. (add link to tinderbox) Install QEMU and kernel acceleration as described in Emulating the XO/Quick Start. See the /Help_and_tips "Development" section.

See #XO-QEMU boot broken - current workarounds.

Build 486 may be working[1]. Otherwise, 445 is still your best bet. 485 and 482 have network issues (and 482 requires an additional workaround [2]).

Overview

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

Note Category:Emulation and Help and tips.

For play, you can use LiveCd or Quick Start.

For development, you can use LiveCd, or qemu (as in quick start, but with a different image), or perhaps one of the Developer Images other than the LiveCd. An alternate approach is to attempt installing sugar. See Getting started programming for a comparison.

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

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

Please report your experiences in User Feedback on Images. There is a Virtualization Common Room.

There are limitations with XO disk images.

The LATEST-STABLE-BUILD versus LATEST build distinction is mostly of interest to people running on actual XO's. In emulation, developers should usually use LATEST. And when STABLE is old, non-developers probably should too.

Comparison of 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, which can each be used in a couple of ways.

recommendations

platform purpose recommendation
Windows development emulated xo disk image; or emulated Ubuntu with sugar-jhbuild; (or develoepr CD or LiveCD)?. (need your reports)
Mac development emulated xo disk image; or emulated Ubuntu with sugar-jhbuild; (or developer CD or LiveCD)?. (need your reports)
Mac with Parallels development install Ubuntu 32-bit, and Sugar on Ubuntu Linux. See /Mac.
Ubuntu 32-bit development Sugar with sugar-jhbuild and Sugar on Ubuntu Linux
32-bit linux development Sugar with sugar-jhbuild
64-bit linux development xo disk images under qemu; or LiveCd once it gets updated (currently it's April)
I don't really believe the development option of Windows/Mac developer/live CD. I've not yet heard of it actually being used. They are months out of date (April). But Mcfletch said (in May) it's an option, so I added it. MitchellNCharity 09:19, 23 June 2007 (EDT)

background

option updated sound? camera? library? etoys? R/W? development software? net? comments
Installing Sugar continuous yes yes? yes? yes yes your own yes On some platforms, it takes time and space (hours and ~3GB), but "just works". On others, it is quite difficult to install.
Installing Sugar, on a virtual 32-bit Ubuntu, running in an emulator (qemu, parallels, or vmware)
LiveCd April yes(boot) yes?(qemu) yes?(boot) no(qemu) no yes no toolchain, Gnome yes? Alternative Quick Start. Can both be booted from, and used in qemu. Problems: A.
XO disk images:
LATEST-STABLE-BUILD http://olpc.download.redhat.com/olpc/streams/development/LATEST-STABLE-BUILD/
...development-ext3.img ~monthly yes/B no yes yes yes no after config Quick Start for getting a look at Sugar.
...development-devel_ext3.img ~monthly yes/B no no yes yes a little after config
LATEST http://olpc.download.redhat.com/olpc/streams/development/LATEST/
...development-ext3.img ~daily yes/B no yes yes yes no after config
...development-devel_ext3.img ~daily yes/B no no yes yes a little after config Good for new developers (requires some command-line comfort).
OTHER
FC6+Sugar April yes?  ?  ? no yes Full Fedora Softare Dev. yes 6GB (April version: no etoys)

Key:

library: A library of sample content is included (english version). Ie, pretty text to web browse without having to get network.
R/W (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?
Net (network): does the network "just work" or "manual" steps are required?

Problems:

A: LiveCd (April) on fc6 x86_64, kernel panics under kqemu. A squashfs problem.
B: Tam Tam is silent (though EToys makes noise). Cause unknown.

Notes:

  • re "does sugar-jhbuild support camera/mic?": "yes, if the camera uses v4l2 and 640x480, I'd suspect so." Can someone confirm this? (#olpc, now) MitchellNCharity 00:16, 2 June 2007 (EDT)

Doables:

  • Remove LiveCd's "?" above.
  • Find out what's going on with Tam Tam sound. It would be nice for the xo disk images to all be sound-yes.
  • Add a microphone column? Reconsolidate sound/camera/mic into a H/W column?

XO-QEMU boot broken - current workarounds

Build 445 was the last version which booted cleanly under qemu (ticket). More recent builds require workarounds. Build 485 resolved one problem.

  • When booting on qemu, add root=/dev/hda to the grub kernel line. This needs to be done every time.
    1. When you start your xo disk image on qemu, you should see a blue grub screen, doing a "Booting .. in N seconds" countdown. Press space to interrupt it.
    2. Press e (edit). This will show you 3 lines.
    3. Move to the second, which begins "kernel". Press e. This will take you to the end of the kernel line.
    4. Add root=/dev/hda1 Then press enter.
    5. Press b to continue booting.
(This workaround avoids "WARNING: Cannot find root file system!", and being dropped into an emergency shell.)

Should add instructions to modify the image's grub config, so this doesn't need to be done every time you boot. MitchellNCharity 12:04, 3 July 2007 (EDT)

It might be worth gathering the currently scattered notes, into a single list of step by step instructions, for getting from nothing, to a pair of qemu images running with Xephyr's and ssh. MitchellNCharity 12:04, 3 July 2007 (EDT)

Example step-by-step instructions

Here, in one place, are assembled all the steps to get you to a working emulated XO. Assuming you are running on linux, and have already installed qemu and kqemu.

The following will not work on your virtual xo: sound, camera. The first because I haven't gotten around to figuring out why it isn't working. The second because qemu doesn't yet support them.

And when you boot your image a second time, network likely won't work. :( Something for another day. MitchellNCharity 16:49, 4 July 2007 (EDT)

Go to http://olpc.download.redhat.com/olpc/streams/development/LATEST/devel_ext3/ and obtain the numbered -devel_ext3.img.bz2 and its md5. For this example I used build 485. Though the network doesn't seem to work in 485. 482 works, but you have to work around a boot failure. [3]

md5sum -c olpc-redhat-stream-development-build-485-20070703_0249-devel_ext3.img.bz2.md5

bzcat olpc-redhat-stream-development-build-485-20070703_0249-devel_ext3.img.bz2 > xo-485a.img

The resulting file is 1 GB.

export PORT=2221
qemu-system-x86_64  -soundhw es1370 -serial `tty` -kernel-kqemu -redir tcp:$PORT::22 -hda xo-485a.img

Unless you have a x86_64 cpu, use qemu instead of qemu-system-x86_64.

The screen will very briefly be black, and then show the blue "GNU GRUB" screen. If it stays black, that's a qemu bug. Kill qemu and try again.

0. Press any key to interrupt the countdown to boot. Then,

  1. Press e.
  2. Press down-arrow to get the "kernel" line.
  3. Press e. This takes you to the end of the kernel command line.
  4. Type space and root=/dev/hda1
  5. Press Enter.
  6. Press b.

The boot messages will scroll by, and you should eventually see the normal XO first-time login. We'll save that for later.

In the window where you started qemu, you should now see a login: prompt.

  1. Enter root
  2. Then:
/etc/rc5.d/S98NetworkManager stop
mv /etc/rc3.d/S98NetworkManager /etc/rc3.d/DISABLED-S98NetworkManager
mv /etc/rc5.d/S98NetworkManager /etc/rc5.d/DISABLED-S98NetworkManager
echo ifup eth0 >> /etc/rc.local

mv /boot/grub/grub.conf /boot/grub/grub.conf.orig
awk '/kernel/ {print $O,"root=/dev/hda1";next} {print}' < /boot/grub/grub.conf.orig > /boot/grub/grub.conf
grub-install hd0

If grub-install hangs, just kill it. It may even have worked anyway.

ifup eth0 
killall X

Killing X should restart sugar.

If you want to enter a name with diacritics, you need to wait for X to restart, and then do:

su olpc -c"DISPLAY=:0 xmodmap -e 'keycode  77 = Multi_key'"

This sets up Num_lock as Multi_key. Unfortunately, the next time X is restarted, you will lose it. A better solution is needed.

At this point you could just proceed to use your new XO. However, the screen resolution is wrong (1024x768). So for development, or to get a more accurate feel for how things really look, some extra steps are required.

Once you reach the main sugar screen, you should check the Neighborhood view (F1). If you can't see other people, either the we are having problems with the presence server, you are behind an unusually picky firewall, or networking on qemu is broken again in the build number you are using. (Remember that ping doesn't work inside of qemu).

While this next step is not strictly required, it will enable you to use ssh and scp, which can be handy to move stuff back and forth between your host and xo.

Still as root on the xo,

1. Change the root password.

passwd

Don't worry if it says something like "BAD PASSWORD: ", and complains about the password you picked. It will still work.

2. Change the olpc password.

passwd olpc

Now you can use ssh and scp.


The current released version of QEMU doesn't support 1200x900, so we use a Xephyr remote X server. Each time you boot the xo, if you want 1200x900, you'll need to do these next steps again, except for the ones marked "(First time only)".

1. Still as root on the xo:

init 3
sleep 5
ifup eth0

su olpc
grep export /usr/bin/sugar > ~/env
source ~/env

If the ifup eth0 fails with an "already running" message, that's ok. Perhaps it is no longer needed.

2. Back on the host, prepare Xephyr (First time only)

mcookie > xephyr-cookie
export COOKIE=`cat xephyr-cookie`
rm -f xephyr-xauth; echo "add :1 . $COOKIE" | xauth -f xephyr-xauth
echo $COOKIE

3. On the xo, still as "su olpc", record the cookie: (First time only)

echo "add 10.0.2.2:1 . " PUT-THE-COOKIE-HERE | xauth

4. Back on the host, start a Xephyr:

Xephyr :1 -auth xephyr-xauth -reset -screen 1200x900x16 -dpi 200

You will probably want to do this in its own window, as it periodically dies and needs to be restarted.

5. On the xo, still as "su olpc", start sugar:

DISPLAY=10.0.2.2:1 sugar

Actually, I usually ssh in from the host, and run sugar that way:

a. On the host,

ssh -o NoHostAuthenticationForLocalhost=yes -p 2222 olpc@localhost

b. in the resulting shell,

source ~/env
export DISPLAY=10.0.2.2:1
sugar

You may also want to run

xmodmap -e 'keycode  77 = Multi_key'

to be able to enter diacritics with the Num_lock key. But I find doing it first thing tends to kill Xephyr. :(

You should now see the XO first-login screen in correct resolution. You can use Num_lock to enter diacritics. Congratulations. Sorry it was so much bother.


To run multiple xo's (to play with collaboration, for instance), you can repeat the above steps. Create a xo-485b.img, and use a different PORT number (like 2222). If you are using Xephyr, start a second Xephyr, which will be 10.0.2.2:2, use that instead of ...:1 in the instructions. You should now be able to see yourself, and collaborate in Write.

The following will save you having to periodically type your xo password, but is optional, and can just as easily be done later.

Back on the host,

1. Create an ssh key if you don't already have one. See /Help_and_tips#SSH into qemu, using a key.

2. Copy it to the xo,

scp -o NoHostAuthenticationForLocalhost=yes -P $PORT ~/.ssh/id_rsa.pub root@localhost:~/

3. On the xo, spread the key around:

mkdir ~root/.ssh
mkdir ~olpc/.ssh
cat id_rsa.pub >> ~root/.ssh/authorized_keys
cat id_rsa.pub >> ~olpc/.ssh/authorized_keys

You can now ssh and scp without retyping your password.

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