[OT] Raspberry Pi, was: Re: Intel junk...Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign

[Simon Clubley]

On 2018-01-11, johnwa...@yahoo.co.uk <johnwa...@yahoo.co.uk> wrote:
>
> The Raspberry Pi exists because one of the founders,
> Eben Upton, who at the time was teaching at Cambridge
> University, got seriously concerned about the lack of
> understanding shown by his undergraduate intake. This
> too is widely documented, e.g. Eben Upton's IET Young
> Professionals lecture from 2012 (around 45 minutes):
> https://www.youtube.com/watch?v=-P46sRDDONI
>

The Raspberry Pi is ok if you just want to use a supplied version
of Linux and run applications on top of Linux but it is an absolute
disaster area if you want to use it at a lower level with bare metal
programming.

Here's a simple example: feel free to show me the freely downloadable
location for the official datasheets and manuals for the Raspberry Pi's
USB controller.

They are not available unless you are a customer of the vendor who
supplied the USB controller for the Raspberry Pi.

This doesn't even cover all the historical problems with getting data
on the Raspberry Pi's GPU and the last time I checked some of that
information was still closed to the public.

For example, the initial boot sequence on the Raspberry Pi uses a couple
of closed source files which you have to place on the SD card. This is
because the initial boot sequence is controlled by the GPU and not the
ARM MCU.

The ARM MCU is actually held in reset for the first part of the boot
sequence until after the GPU has finished initialising the hardware
and the last time I checked, this boot code was totally opaque; there
was no public documentation available which would allow you to write
your own initial boot code.

So much for the Raspberry Pi being an excellent hobbyist or learning
platform.

Simon.

--
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world

[Jan-Erik Soderholm]

The Raspberry-PI is an excellent platform for its intended use.
It is of course not that good if you try to use it outside of it
intended use. Like using VMS as your desktop/office platform.

[johnwa...@yahoo.co.uk]

Pi isn't a panacea. Needs vary, so do solutions.

Pi is a better teaching platform for many purposes than
most of the alternatives, for loads of reasons that have
been done to death elsewhere. It's not even all about
the products - there is a momentum and a community behind
Pi of a kind which hasn't been seen for a while, and that
in itself adds something.

Some folks even find Pi products are an OK deployment
platform for some kinds of requirements, e.g. where
there is need for simple low cost readily available
physical IO (stuff which is readily available and
affordable in the Pi community and likely to stay so,
not buy ten milliona and we'll tell you about it, but
if you want another ten million in a year it'll likely
have changed by then).

Needs vary, so do solutions.

Having some understanding of what goes on beyond the
mouse can sometimes help people in understanding the
difference between appropriate and inappropriate - as
you've just demonstrated. What looks good on paper
may come with hidden snags, as I found when I did my
first ARM-based comms gateway project ages ago.

Based on StrongARM running MontaVista Linux, in an
industrial box maybe A5 size, it seemed to fit the bill
perfectly. Until we wanted to put our modified kernel
into flash where it could autoboot. The device vendor
didn't want to document how to do that, and there were
some challenges with the local IT department allowing
non-Wintel kit onto the corporate LAN.

Just the kind of thing that Pi might come up against,
except that sensible people nowadays will at least have
heard of Pi but may not have heard of MCUs or Beagles
or PCI/104 or whatever.

TLDR: Pi's good at a lot of things, and it's cheap
and fashionable. Just because something's fashionable
doesn't mean it fits everywhere, does it.

[MG]

Op 11-jan-2018 om 16:20 schreef Jan-Erik Soderholm:

> The Raspberry-PI is an excellent platform for its intended use.
> It is of course not that good if you try to use it outside of it
> intended use. Like using VMS as your desktop/office platform.

Did you read (or even see) what he was responding to?

- MG

[Jan-Erik Soderholm]

I responded to the rambling against Raspberry PI.

And yes, I saw the original post Simon replied to.
Doesn't change my views or comments.

[MG]

Op 11-jan-2018 om 17:28 schreef Jan-Erik Soderholm:

> I responded to the rambling against Raspberry PI.

What was so aimless about what he said? He was quite
specific and elaborate with his criticism.

- MG

[Paul Sture]

On 2018-01-11, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
> On 2018-01-11, johnwa...@yahoo.co.uk <johnwa...@yahoo.co.uk> wrote:
>>
>> The Raspberry Pi exists because one of the founders,
>> Eben Upton, who at the time was teaching at Cambridge
>> University, got seriously concerned about the lack of
>> understanding shown by his undergraduate intake. This
>> too is widely documented, e.g. Eben Upton's IET Young
>> Professionals lecture from 2012 (around 45 minutes):
>> https://www.youtube.com/watch?v=-P46sRDDONI
>>
>
> The Raspberry Pi is ok if you just want to use a supplied version
> of Linux and run applications on top of Linux but it is an absolute
> disaster area if you want to use it at a lower level with bare metal
> programming.
>

See video @ 34:30 "Add-on boards". Eben says that he's a software guy,
and making a dot move around on a screen isn't as cool as it once was;
what kids today find interesting is making a little thing move around on
the floor.

He goes on to argue that the Pi should not be seen as a competitor to
the Arduino but as something which is complementary.

"What good about Arduino? Very low power and very low cost."
"What's bad about Arduino? You need a host PC to run it from"
"What does a Pi give you? It's a very very very cheap host PC"

> Here's a simple example: feel free to show me the freely downloadable
> location for the official datasheets and manuals for the Raspberry Pi's
> USB controller.
>
> They are not available unless you are a customer of the vendor who
> supplied the USB controller for the Raspberry Pi.
>
> This doesn't even cover all the historical problems with getting data
> on the Raspberry Pi's GPU and the last time I checked some of that
> information was still closed to the public.
>
> For example, the initial boot sequence on the Raspberry Pi uses a couple
> of closed source files which you have to place on the SD card. This is
> because the initial boot sequence is controlled by the GPU and not the
> ARM MCU.
>
> The ARM MCU is actually held in reset for the first part of the boot
> sequence until after the GPU has finished initialising the hardware
> and the last time I checked, this boot code was totally opaque; there
> was no public documentation available which would allow you to write
> your own initial boot code.
>
> So much for the Raspberry Pi being an excellent hobbyist or learning
> platform.

I think you are overestimating what it's supposed to be. Like Eben
stated, there are other bits of kit for the hardware enthusiasts.

Have you looked at any of the pure beginners tutorials that are
available out of the box with a Pi? The first one I looked at
really had me thinking "Wow, I would have loved this stuff at the
age of 7 or 8". It was something like a simple text triangle but
it was a pretty good introduction to mathematical progressions.

--
Macs. They used to smile at you.

[Simon Clubley]

On 2018-01-14, Paul Sture <nos...@sture.ch> wrote:
> On 2018-01-11, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
>>
>> So much for the Raspberry Pi being an excellent hobbyist or learning
>> platform.
>
> I think you are overestimating what it's supposed to be. Like Eben
> stated, there are other bits of kit for the hardware enthusiasts.
>

The problem is that the Raspberry Pi is a really good bit of hardware
for some of the lower level things I would like to use it for.

The only thing which is missing is the documentation.

> Have you looked at any of the pure beginners tutorials that are
> available out of the box with a Pi? The first one I looked at
> really had me thinking "Wow, I would have loved this stuff at the
> age of 7 or 8". It was something like a simple text triangle but
> it was a pretty good introduction to mathematical progressions.
>

I understand what you are saying, but there's no reason why it
couldn't be both. It's especially annoying because some of the
other low cost and small form factor boards also come with poor
documentation (for example, the Allwinner based boards I have
looked at.)

On the plus side, some of the MCU manufacturers (such as TI) are
a lot better at the documentation. I just wish TI didn't have
some daft download export controls. (When I tried to download
some demo code from TI several years ago, I was routed to some
export control page and was never able to download the code...)

[Paul Sture]

On 2018-01-14, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
> On 2018-01-14, Paul Sture <nos...@sture.ch> wrote:
>> On 2018-01-11, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
>>>
>>> So much for the Raspberry Pi being an excellent hobbyist or learning
>>> platform.
>>
>> I think you are overestimating what it's supposed to be. Like Eben
>> stated, there are other bits of kit for the hardware enthusiasts.
>>
>
> The problem is that the Raspberry Pi is a really good bit of hardware
> for some of the lower level things I would like to use it for.
>
> The only thing which is missing is the documentation.

Understood.

>> Have you looked at any of the pure beginners tutorials that are
>> available out of the box with a Pi? The first one I looked at
>> really had me thinking "Wow, I would have loved this stuff at the
>> age of 7 or 8". It was something like a simple text triangle but
>> it was a pretty good introduction to mathematical progressions.
>>
>
> I understand what you are saying, but there's no reason why it
> couldn't be both. It's especially annoying because some of the
> other low cost and small form factor boards also come with poor
> documentation (for example, the Allwinner based boards I have
> looked at.)

Hasn't it ever been thus, with a disconnect between the hardware guys
and software guys?

Have you let the Pi folks know about this? As I mentioned, from the
video Eben Upton is a self admitted software guy who didn't realise that
so many would be interested in the hardware side of things. It's
possible that he didn't ask for public documentation simply because he
didn't realise there would be a demand for it.

> On the plus side, some of the MCU manufacturers (such as TI) are
> a lot better at the documentation. I just wish TI didn't have
> some daft download export controls. (When I tried to download
> some demo code from TI several years ago, I was routed to some
> export control page and was never able to download the code...)

I've had similar frustrations.

P.S. As far as I am aware, the iTunes EULA still contains a clause
about not using it in the development of nuclear power stations.

I'll leave you with a quote from Elliott Roper on that:

"iTunes has long ago reached Arthur C. Clark levels of magic."

:-)

--
As we've seen time and time again, the Internet of Things is
demonstrably as robust and secure as a kitten crossing a motorway.
-- Alistair Dabbs

[Simon Clubley]

On 2018-01-16, Paul Sture <nos...@sture.ch> wrote:
> On 2018-01-14, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
>>
>> I understand what you are saying, but there's no reason why it
>> couldn't be both. It's especially annoying because some of the
>> other low cost and small form factor boards also come with poor
>> documentation (for example, the Allwinner based boards I have
>> looked at.)
>
> Hasn't it ever been thus, with a disconnect between the hardware guys
> and software guys?
>

Sadly, yes. However some organisations are better at this than others.

> Have you let the Pi folks know about this? As I mentioned, from the
> video Eben Upton is a self admitted software guy who didn't realise that
> so many would be interested in the hardware side of things. It's
> possible that he didn't ask for public documentation simply because he
> didn't realise there would be a demand for it.
>

_Many_ other people appear to have gone down this path before me.

In the case of the USB controller, it appears that Broadcom bought in
the USB controller for their MCU from a third party but with conditions
attached which means they cannot redistribute the documentation freely.

[Paul Sture]

On 2018-01-16, Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> wrote:
>
>> Have you let the Pi folks know about this? As I mentioned, from the
>> video Eben Upton is a self admitted software guy who didn't realise that
>> so many would be interested in the hardware side of things. It's
>> possible that he didn't ask for public documentation simply because he
>> didn't realise there would be a demand for it.
>>
>
> _Many_ other people appear to have gone down this path before me.
>
> In the case of the USB controller, it appears that Broadcom bought in
> the USB controller for their MCU from a third party but with conditions
> attached which means they cannot redistribute the documentation freely.
>

Thanks for letting us all know. I for one didn't realise it the obstacle
was there.

One day, Rodney...