
Raspberry Pi interview: Eben Upton reveals all - cpeterso
http://www.linuxuser.co.uk/features/raspberry-pi-interview-eban-upton-reveals-all/
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rmk2
> Ubuntu got in touch with us to say ‘how can we stop you saying that Ubuntu
> runs on Raspberry Pi?’ Which I thought was pretty brutal, actually. So,
> yeah: they don’t support our chip, they’re not interested in supporting our
> chip, they’ve been quite vocal about trying to stop us from saying Ubuntu,
> so we stopped saying Ubuntu.

Way to go, Canonical...

You want to make Ubuntu _the_ Linux desktop, yet you can't be arsed to support
one of the cheapest and easiest solutions to run it on? The Raspberry Pi is a
_brilliant_ way to introduce children and adults alike to linux, and Ubuntu
doesn't deem it worthy of supporting that effort...

~~~
nextparadigms
In their defense, ARM11 _is_ a 10 year old chip. I don't think they want to
support such an old legacy. Does Windows 7 support Pentium 2?

Still, I'm hoping Raspberry Pi moves to Cortex A7 as soon as it's available,
which is based on the ARMv7 architecture, and Canonical might support it then.

~~~
masklinn
The PII is 15 years old at this point, 10 years ago was Northwood p4 and the
Athlon XP for AMD

Those chips _started_ at 1.6 and 1.33GHz respectively, and Windows 7
requirements start at 1GHz. RAM might be a dicier issue (W7 requires 1GB) and
I don't know the state of the chipset drivers, but technically W7 probably
supports x86 chips from 10 years ago.

~~~
obtu
i586 has stayed backwards-compatible (although performance isn't the same if
you don't know what you're targeting), ARM hasn't. The raspberry pi's ARMv6 is
very different from a Cortex's ARMv7. The kernel also needs patches to know
how to initialise an ARM device, and those patches need to be forward-ported.

~~~
masklinn
I'm not denying that, I'm just saying nextparadigms's argument of chip age
does not hold any water.

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jsmcgd
What's Canonical playing at? Surely the Raspberry Pi represents a golden
opportunity to steal massive amounts of mind share. They could establish
themselves as the computing environment amongst the next generation of
computer users.

~~~
robot
"Ubuntu got in touch with us to say ‘how can we stop you saying that Ubuntu
runs on Raspberry Pi?’ Which I thought was pretty brutal, actually."

As a HW engineer he overlooked hidden software complications with ARMv6
chipset. The ARMv6 chipset is old, its virtually tagged/indexed caches have a
plethora of cache aliasing issues that reflect to workarounds in linux kernel
and shared libraries in userspace. You have to maintain an entire ARMv6 distro
for this arch. I would personally not use anything non ARMv7, because all
these issues are resolved in ARMv7.

So its quite natural Ubuntu did not want to allocate a team of 100k/year
engineers for raspberry pi, and protect its brand also.

For the curious, if you map the same physical address to 2 virtual addresses,
and both happen to be in the cache, you have 2 virtual entries in the cache
for the same address, so which one to flush back to RAM is ambiguous. Its a
problem specific to virtually addressed caches. Solution: a lot of
restrictions to avoid aliasing and you flush the caches too often to avoid
aliasing etc.

~~~
rdtsc
Thanks for explaining. Ubuntu's approach makes sense then. Wonder how much
more expense v7 would have been.

I see the problem with Raspberry Pi being the software and the SDK. It is a
very elegant and appealing piece of hardware but that only gets them there
half way. The other is the manuals, the sdk, some kind of recipe exchange or
cookbook for basic things.

Also, it looks like Arch Linux has stepped up to replace Ubuntu.

<http://www.raspberrypi.org/> (March 4th, post)

~~~
bane
It sounds like that's the reason for the Pi in the first place? A simple piece
of hardware hobbyists can target software to.

~~~
rdtsc
Once it has USB, Ethernet, and HDMI it is not your uncle's bare 8 bit micro-
controller anymore. Yeah developers could sit and each write a different
version of HDMI driver, but wouldn't be too much fun. One would expect there
to be a nice SDK and libraries to access and make use of all those hardware
features.

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yardie
So what was the technical problem that caused the ship date to be pushed into
late February?

~~~
freehunter
If I remember correctly, one of the chips they had in mind when designing the
board was no longer in production, or the price had gone up.

Actually, I looked it up and yes, one of their components had been replaced
and they had to design for the new version.
<http://www.raspberrypi.org/archives/615>

-edit: sorry, after re-reading it, it doesn't seem like they designed for the new one, they just had to wait while the factory found enough of the old version. But that's why it was delayed.

~~~
jacquesm
Par for the course in the hardware world, one of the reasons why I'm very
happy my soldering iron has retired.

The probability of a chip being eol'd for <insert random reason here> is
inversely proportional to the number of pin compatible replacements made by
alternate sources.

~~~
beagle3
And that makes perfect sense: If something is essentially guaranteed to sell
well, competitors would produce it as well. If something is not selling well
enough to produce compatible replacement, then it is likely marginally
profitable to produce or not at all.

