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Re: Status for non constrained embedded systems

On 2007-05-10 10:59 +1000, Brendan Simon wrote:
> Dear Emdebian Developers.
> It seems the main focus of emdebian is for more deeply embedded systems, 
> such as iPAQ.  As such there is a lot of work to get a small rootfs by 
> using busybox, uclibc, etc.  Other things like GTK+ are also of interest 
> to an iPAQ but not necessarily other types of embedded systems.

[Just a bit of quibbling - I take your general point]:

I'd have thought GTK was pretty widely needed - most systems with
a GUI (except the _really_ embedded ones that might use
somethinglighter wieght).

The ipAQ is a focus because Neil has one. I wouldn't call it 'deeply
embedded' myself, although by dint of age his model is headed that way
:-) It's certainly toward the lower-resource end.

> The embedded systems that I work on are larger 1RU communications 
> equipment with lots or processor grunt (PowerPC), RAM, Flash, etc.  
> Packages of interest for comms equpiment would be snmp (net-snmp), web 
> server (apache), remote terminal (telnet, openssh), security (openssl, 
> openswan), etc.  I do not see the need for uclibc, as glibc would be a 
> lower risk due to its wide spread use.  I do see that busybox does have 
> an advantage if managing/building from sources as it is a single 
> package, but if using pure debian sources then the other packages that 
> busybox replaces is also equally valid.
> I was wondering what the status off emdebian is for this type of system?

Less advanced, as you observe, but there is nothing about the emdebian
tools that particularly favours the 'depply embedded' end. The idea is
to include all the packages in debian that anyone asks for. 

We have simply started with a small busybox based rootfs as that is
fewer packages to get going with.

If you look at the rootfs page, you will see that there is a standard
'debotstrap list' rootfs package list too. Make all those build under
emdebian tools and we have 'debian-equiv' emdebian rootfs.


What isn't entirely clear is how we will manage variations like these.
I think it is perfectly do-able to have the deps for the base system
such that you can simply choose whetherto have it gnu-based or
busybox-based, so that's easy. But later on we may hit areas where
simple compromise is not sufficient to satisfy everyone - we will see.

Emdebian stuff is currently all glibc-based, although we would like to
build a uclib-based version too, but that needs toolchian stuff

> Using the emdebian cross-tools (eg. on Etch/AMD64 build machine), could 
> I generate a PowerPC rootfs (linux, glibc, net-snmp, openssh, apache, 
> etc) from the debian sources?

Yes (except that some packages don't cross-build right now). And a few
probably don't even native-build. The rootfs page is currently the best
guide to what is still missing, but we will clearly soon need some
build-log infrastructure a bit like debian's to show which builds of
which packages work/don't work, to make it easy for someone like you
to target your efforts.

> Given it is more like a workstation filesystem, just cross-compiled from 
> debian sources, would emdebian be more advanced for this type of 
> development than for a deeply embedded system such as an iPAQ?
> I want to start a development team on a new project in the next month or 
> so, with the intent of having a stable rootfs by Q4/2007.  Will emdebian 
> be stable enough for this?  

> At the moment it seems to moving very  quickly which is great, but also risky.

That's a fair summary. 

It most definately is targetted to meet your needs, so if it doesn't
something is wrong. The other possible way to do what you want is use scratchbox.

All you should have to do is install emdebian-tools, emsource each
package you want then make it cross-build (and check the results back
in to emdebian svn - I can sort you out access). This last step varies
from trivial to epic depending on package. Most are fairly painless.

Ideally the changes you need to make can be filed as upstream
cross-compile bugs rather than kept as emdebian patches.

If you want it stable for Q4 then you will need to put some work in,
exactly how much depends on how many packages you need, and how many
others get involved.

Principal hats:  Balloonz - Toby Churchill - Aleph One - Debian

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