Re: Mojo

[Miko Nieminen <miko nieminen nomovok com>]

On Wed, 2008-07-23 at 12:16 +0200, Florian Boor wrote:
> Hi,
> 
> Miko Nieminen schrieb:
> > I think that could be very interesting base for Gnome Mobile development
> > or at least one of the development environments. Especially since it
> > brings the power of Ubuntu (and in the future why not also full Debian)
> > into mobile devices with better optimisation than what normal Debian
> > allows (though currently they are using kind of dirty way of bringing
> > those optimisations). Of course it is just ARM port, but this same
> > approach allows porting to other architectures too. Check Andrew's
> > presentation about the subject, it's quite good:
> 
> well, I do not see much of of benefit from this project. Its just a desktop
> distribution built for ARM devices. Like you mentioned there is Debian for ARM
> already and Mojo does not provide a useful environment for mobile devices... its
> a desktop distribution.

It's true that since Ubuntu is desktop distribution Mojo is too, but
being desktop distribution doesn't make mojo interesting. What makes it
interesting is the fact that it is full distribution and there are
corresponding x86 version (Ubuntu) and ARM versions (Mojo). Basically
the interesting part is just a subset of Mojo, subset which defines
Gnome Mobile.

So the real value comes from the fact that almost everything is already
build as Debian packages and thus you just select your packages and
start building your applications on top of those. And if you need some
additional dependencies there are good possibilities that the
distribution provides those already.

> Its nice to see that most of the desktop applications work on ARM as well, but
> for Gnome Mobile distributions that target mobile devices such as Angstrom and
> Poky are much more interesting.

Once again desktop side isn't the thing, but once again the fact that
Mojo is a complete distribution.

Ångström is very interesting as a distribution, but it is build around
OpenEmbeded which is build around cross-compilation like Maemo and
that's what we want to get rid of.

Mojo goes with native builds (currently by using Qemu) like Debian and
I'm in favour of that approach. Using native build just works much
better, check that Andrew's presentation. With cross-compilation you
need to be quite careful about which versions of different tools to
select for your toolchain, with native build you don't have that many
problems.

If I remember correctly building Ubuntu Feisty with Scratchbox, they
were able to build something like 20-25% with out patching and with
native build same number was around 80%.

What comes to Poky, I haven't checked it that well, but isn't it also
cross-compilation environment?

So far my experiences have been very positive with Mojo and we've be
doing our things on top of it from the early days. Basically we have
completely virtualized x86 environment which is configured to match our
device images and we make our development completely inside it. Then we
have ARM build images where we build our ARM packages which can be
installed to the actual device. Basically this was the original idea (I
suppose also current too) with Scratchbox, but having real virtualized
environment over chroot-jailed environment just works much better for
testing the whole system and running it as x86 is just much more
efficient and you have better tools available.

Distribution doens't need be Mojo, but currently it is the distribution
with which we have had least problems and which provides quite nice
optimisations. Performance differences between ARMv5EL and ARMv6EL-VFP
are quite noticeable and I suppose difference to Debian's ARM EABI port
is even greater.

Any way my actual intention was to point out the existence of Mojo,
since we have had lot's of good experiences with it. Previously we were
using Maemo, but it was giving us way too much of headache so we end-up
trying Mojo and our people have been very satisfied from this move. I
have to see if I can put our development environment and images out so
that people could try this approach, but in any case you can build our
own quite easily.

br,
-- 
Miko Nieminen
+358 40 8228047
miko nieminen nomovok com