[okl4-developer] Platform recommendations

[Josh Matthews]

Hi David,

>> This is definitely plausible. The best ARM architecture and simulation
>> environment to get started with out of the box is Gumstix (PXA255) with
>> the Skyeye simulator. Full instructions on how to do that are up at
>> http://wiki.ok-labs.com/Prerequisites.
>
> Thanks very much, that works like a charm.

That's great to hear!

> For reference, the standard
> package of skyeye that comes with Ubuntu Heron (and therefore, I assume,
> Debian) appears to work fine, and is much more recent than the one in
> the wiki. Also for reference, skyeye's web page is down (database
> failure from the error message) and so there is no manual...

Seems it's their old wiki site that's down - try
http://skyeye.wiki.sourceforge.net/. The manual is accessible from there.

> Can I build OKL4 with more recent versions of gcc than 3.4?

I believe so - 3.4 is just what we support. Would be interested to hear
your experience with doing so.

>> Yes, you can use just the OKL4 (Pistachio) kernel. Take a look at the
>> l4test project in the latest release for an example of how that is done.
>
> I have been. The build system is very scary. But I have only been
> looking at it for 30 minutes so far.

The build system can be a bit daunting the first time you look at it,
particularly if you're unfamiliar with SCons. Feel free to post any
questions you have about it here - we'd be glad to help.

> And now, unfortunately, some boring legal stuff...
>
> What license is OKL4 distributed under? The wiki doesn't have one I can
> find, there's no overall license document in the source distribution,
> and the technical FAQ simply says 'an open source license' without
> actually saying which one. Each source file has a license at the top of
> it; is this the same for all files? If so, what *is* it? It seems to be
> a viral GPL-a-like, which is fine, but I don't recognise it. There are a
> couple of references elsewhere to OKL4 being BSD licensed, but that
> license certainly isn't any kind of BSD I've seen before. Can I get
> clarification before I start doing too much work?
>
> (Sorry if this seems overly pedantic, but I've been burned before on
> projects based on code with dodgy licenses, which now turn out to be
> really hard to distribute and therefore not really any use to anyone. So
> I'd like to get this sorted out beforehand.)

(Usual disclaimer: I am not a lawyer, etc.) Completely understand your
concern regarding licensing. To be clear: the OKL4 source is distributed
under a dual open-source/commercial license. Use of OKL4 under the open
source license requires that the source code for the software using OKL4
also be made freely available. In the event you do not want to make your
source code freely available, you can purchase a proprietary use license
for OKL4.

The exact terms of the license are available in the header of each file in
the source distribution. If you're unfamiliar with dual licenses, one such
as this is widely considered to be "Sleepycat"-style
(http://en.wikipedia.org/wiki/Sleepycat_Software).

OK Linux, being additions to the Linux kernel, is of course released under
the GPL. On a historical note - some very early versions of OKL4 were
BSD-licensed, so that is probably what the references you have seen are
referring to.

Best regards,

Josh Matthews