Pi vs BeagleBone-Black

Ervin Kosch wrote:

  I was one of the first people to say my preferences (RPi Model A for small stuff because of power consumption and BBB for large projects because it has more of the features I'm looking for like IO.)

I'm curious what your power consumption figures are like for the model A as the BBB SRM has some interesting power consumption figures that on paper appear a good deal better than the B under somewhat similar circumstances.

Ervin

I'm all up for a good debate, however this (from an outsiders view point) has turned into something else, resembling kids squabbling over he said, she said.

I think everyone needs to take a deep breath, and quieten down.

I've seen a written sentence interperated different ways by different readers before, and neither reader got it right, because that wasn't the way it was intended.

It just so happened that the writer hadn't phrased it as well, hence it wasn't as clear as they intended.

I'm sure both boards will have their place in our world, and one might be favoured over the other for xyz reason(s).

I haven't seen a direct comparison between the both to enable a begineer to make choices.

I'm sure that with all the intellect in this group, we should be able to draw up a chart, so that someone could do that, and yes price may be one factor.

So how about it people?

cheers

Mark

Incidently, (just to have some concrete references for anyone curious to explore that path, although I agree it's a slight digression now, not really discussing the beagleboard specifically), there are some RTOSs that have so-called 'low' latency, even the extremely common uC/OS (I think the code is free - otherwise is available with the author's book) manages tens of usec with (say) a 16MHz clock. Probably nothing stopping people from porting it to this processor, although I'm personally not interested. Another commercial example is EOS (a very old operating system developed by Etnoteam, Italy. It is multitasking and can support real time applications. Versions were available for the Intel 8086 and old Motorola devices. The basic version occupies approximately 4kbytes of ROM, but this rises to tens of kb for the complete system.It was modular and was intended for a variety of applications). I found this report of its performance on an ancient ARMv3 running at 25MHz (scheduling/context switch time is fairly low). But, even tens of usec is useless for many tasks like the robot arm example.

There were other RTOSs with this ballpark of latency. Another example is Hitachi's HI8 which achieved good results on another ancient processor (H8/500 series, this is from late 1980s, so very old (one can assume the CPU speed was below 16MHz):

Also, agree POSIX compliance is not always required, and is not relevant to small processors like the one on the beagleboard, where you want to write some tight code anyway. For example, Japan had it's own standards for smaller processors. It is generally accepted that some form of process synchronization is needed, scheduling methods, memory management and so on, but all the systems mentioned above implemented these features. POSIX is not always necessary because one may never want to port to another device, or, more commonly, people don't directly use the APIs anyway because often, some higher-level framework is created to abstract away from the raw API, to protect oneself, or to have object-oriented framework possibly, and write better code too.

It's a digression, but useful to know about the choices for the small processors.

Having said all that, if I wanted to interface to any hardware (most hardware) that requires reasonable timing, I too wouldn't be interested in running Linux nor any OS for high/average-speed tasks (coding with interrupts is perfect for many use-cases), nor real-time Linux; I would use Linux for tasks that I don't mind to have more latency (e.g. UI update) or where it's too hard to re-write vast libraries of code that already exists on Linux.

So, for me, I'm looking forward to trying the board, because I don't like bringing out ISE and having to prototype a board just to have some (averagely)high-speed processing going on with external hardware.

Mark,

> I haven't seen a direct comparison between the both to enable a begineer to make choices.

There is a summary comparison for beginners here:

   http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=41489&start=81

I found user gyeben's response interesting, which says:

     "Took a look at the article mentioned in the first post (http://roboteurs.com/beaglebone-black-vs-raspberry-pi/) and that article is clearly unfair to the Pi. 

        | Some people have clocked the Pi up to 1Ghz but its pretty risky.

     It's NOT risky. Overclocking the CPU is not risky at all."

Mark Beckett wrote:

 

I'm all up for a good debate, however this (from an outsiders view point) has turned into something else, resembling kids squabbling over he said, she said.

 

I think everyone needs to take a deep breath, and quieten down.

 

...

 

cheers

Mark

The following comment is to be taken humorously and with hopes that this shadow hasn't offended:  It does seem to the casual observer that some of the above discussion appears to be arguing-for-the-sake-of-arguing rather than a productive exchange of ideas.  Personally, some of it calls to mind a Shakespeare play in which a young man and a young woman are constantly sniping at each other through the first few acts but then they realize that all the arguing is really because of repressed sexual tension and that they're really in love with each other and become an item at the end.

Hmm, now what was the name of that play?

coder27 wrote:

 

Mark,

> I haven't seen a direct comparison between the both to enable a begineer to make choices.

 

There is a summary comparison for beginners here:

   http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=41489&start=81

 

I found user gyeben's response interesting, which says:

 

     "Took a look at the article mentioned in the first post (http://roboteurs.com/beaglebone-black-vs-raspberry-pi/) and that article is clearly unfair to the Pi. 

        | Some people have clocked the Pi up to 1Ghz but its pretty risky.

     It's NOT risky. Overclocking the CPU is not risky at all."

Here's what I wrote at in the same RasPi forum discussion:

What are some of the things you get for that extra US$10 versus RasPi?

 

Faster processor: 1 GHz Cortex-A8 versus 700 MHz ARM11.

Far more I/O pins.

Ethernet that connects directly to SoC instead of over USB.

Two RISC engines for low-level programmable I/O.

BBone white has rounded corners so it actually fits in an Altoids box.  I think BBone black is the same form factor.

 

According to my observations, I would say RasPi has better community support so is a better choice for new users.  IMO Beagle has always targeted developers rather than users -- I don't know if there will be an effort to change that.  Also, it may only be my own impression.

 

[Edit: Beagle does have good community support -- it just seems to me that RasPi's is better and that it's easier for a new user to get up to speed with RasPi than Beagle.  For example, it's easier with RasPi to find a recommended OS version and install it.  JMO/YMMV]

Today I would also add that BBone Black has 2GB eMMC on the board which is pre-loaded with Ångström so it boots right out of the box and is immediately useful.  BBone's Cortex A8 supports other GNU/Linux distros such as Ubuntu which haven't been ported to RasPi.  (Personally, I prefer the Debian on RasPi to Ubuntu on my x86 PC -- chacun a son goût.)

OTOH, for video RasPi's media processor is probably better.  Like Morgaine, I have no need for it so it's not an advantage.

Also, I wrote the above comment before discovering that beagleboard.org had just reformatted their web site and it appears now to be a lot easier to get OS distros (for example).

Luc, Mark and Ervin, I agree completely about the pointless digression into realtime Linux.  That's why I didn't respond to the latest salvo, it's clearly a non-productive argument, so I ended the interchange unilaterally.  The merits or otherwise of realtime Linux are entirely irrelevant to the discussion about BBB versus Pi.  I tried to end it through reasoned discussion, but that failed.  Sorry.

In contrast, the BBB's PRUs are entirely relevant in the comparison, because it's a salient built-in feature of the BeagleBones and is so powerful that it has front-page bullet points on beagleboard.org's BBB page.  It's clear that they rate it highly, and not discussing it in a comparison with Pi would be remiss.

Also, let's not forget that even Eben Upton has publicly expressed support for the idea of coupling the Pi to an Arduino.  He's an engineer, and he knows full well that the gains in interface expansion and in realtime performance are really quite enormous when you combine the two.  Even the Gertboard has a microcontroller on-board, and despite not being an RPF product, it certainly has their blessing.

Well, because of its PRUs, the BBB requires no additional microcontroller to achieve the same kind of gains in interface expansion and realtime performance, so this enters very strongly into the comparison.  Pi can handle a small amount of interfacing without additional hardware, whereas BBB can handle a lot more.  Pi can satisfy very very weak realtime requirements with its standard kernel, whereas BBB can meet very hard realtime constraints with its standard kernel because it has a couple of PRUs that are dedicated to I/O.  For ambitious applications, that's a very big deal.

PS. This was about one feature only, where BBB happens have superior functionality.  Both boards do of course have both pros and cons, that's very clear, and it means that there is no "best board".  There is only "best board for your particular requirements", and so the answer will vary with the person.

Morgaine.

> OTOH, for video RasPi's media processor is probably better.  Like Morgaine, I have no need for it so it's not an advantage.

I think the details are still unclear about the BBB's usability for home theatre.

Apparently it mainly uses the cpu for mpeg decoding.  So does that mean that VLC

will be usable (unlike on the RPi where only omxplayer is hardware accelerated?)

It seems to me it is a bit unfair comparing TI's second generation BB to the RPF's

first generation product.  The RPi's big advantage now is that it is in mass production,

but the BBB is just announced and temporarily out of stock, with no clear idea of how

fast production can be ramped.  We have yet to hear when the RPi's educational release

will be or what it will include, but release 3.0 and/or 2nd generation is said to be coming.

I think it's noteworthy that the BBB is FCC/CE certified for sale to residential users,

but the current RPi as far as I know is not.  I think it's also noteworthy that the BBB

claims to support the Microsoft wireless 800 keyboard.  I think it's noteworthy that the

Fedora ARM folks support the BB directly, rather than indirectly through Seneca as a Remix.

coder27 wrote:

 

I think the details are still unclear about the BBB's usability for home theatre.

How welll it will perform in that role remains to be seen, but one thing is absolutely crystal clear.  It was not designed for that purpose, so if it works well as a media centre it will be as a lucky side effect of providing a working X11 desktop or Arduino UI. (*)

I've now read about half of the BBB System Reference Manual, and they make it abundantly clear that the board was developed to support engineers, technical enthusiasts, makers, and educators+students.  Reading between the lines, and from interacting with the BB community directly, there is considerable {concern,hostility,apathy} towards those that jumped on the Pi educational bandwagon purely because they wanted a cheap media centre.  The views vary of course, but I think it's safe to say that nobody considers the BBB to be a media centre platform, even if it works.

That area still belongs entirely to the Pi, and any competition for media centre eyeballs is unlikely to be coming from the BB stable.

Morgaine.

(*) PS. Lucky side effects are not impossible.  BBB has been shown running Quake 3.

> if it works well as a media centre it will be as a lucky side effect of providing a working X11 desktop or Arduino UI. (*)

Or perhaps as a lucky side effect of supporting Android with Flash and/or html5.

The RPF actively encouraged media centre users, and I think they account for

a significant fraction of sales.  I think a lot of folks justify the purchase by saying

"I'll buy it to learn programming, and if that doesn't work out, I can still use it as a

media center."  So quite a successful sales tactic.