[Newbies] Re: Beginners Digest, Vol 108, Issue 5

14 Jul 2015

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Today's Topics:

Re: Raspberry Pi v. Raspberry St (Casey Ransberger)

Message: 1
Date: Mon, 13 Jul 2015 17:58:34 -0700
From: Casey Ransberger casey.obrien.r@gmail.com
Subject: Re: [Newbies] Raspberry Pi v. Raspberry St
To: "A friendly place to get answers to even the most basic questions
        about   Squeak." beginners@lists.squeakfoundation.org
Message-ID: D0FA7EDA-8261-492F-A974-971786A9614F@gmail.com
Content-Type: text/plain; charset="utf-8"
Hey Kirk,
I like Ralph's suggestion of doing the time/timing specific stuff on a
dedicated microcontroller.
I'd recommend going one better: use more than one microcontroller. Robots
need to do a lot in parallel; if the robot has to stop driving in order to
think, that's a problem (although the converse would be decidedly human!)
Anyway, it sounds like real-time is not negotiable in your view, so green
threads won't cut it either.
Mine has... six controllers in total. That's not counting the ARM9 which
is more like a full computer (e.g., Linux.)
I think six anyway. Could be more hiding in there. Two drive sensors,
three drive motors, one is wired up close to the ARM board to coordinate
the other controllers on behalf of what the Linux system wants them doing.
I'm curious, have you figured out what the average, best, and worst case
latencies are on human reflexes? In my view, matching or beating that
benchmark is where the money probably is.
--C
...
On Jul 6, 2015, at 12:39 PM, Kirk Fraser overcomer.man@gmail.com
wrote:
...
Ralph Johnson,
That's an excellent suggestion and an excellent story, thank you very
much!  Letting the human interface in Smalltalk program the robot
controller instead of being the robot controller sounds good.
...
My robot uses a network of Parallax microcontroller chips to drive
hydraulic valves, which can be programmed via USB for simple tasks like
moving one joint from point A to B but since each controller has 8 cores
more complex tasks like grasping or walking can be done on the MCU's or on
a small Raspberry Pi or other hardware in a non-GC or controllable GC
language.
...
A harder part to wrap my head around is handling the webcam vision
system and artificial intelligence while remaining time sensitive enough to
do time critical tasks like cartwheels and other acrobatic choreography.
...
I know in effect my human mind shuts down most of its intellectual
pursuits when engaged in heavy physical activity - maybe the robot must do
the same - think more creatively when idling and pay closer attention while
working. That takes care of the Ai timing.
...
The heavy load of vision processing appears to need a mini-cloud of
cores to reduce time to identify and measure objects from contours and
other information.  To guarantee performance they would also need to run a
non-GC language that could be programmed from Squeak interactively as new
objects are being learned.  I haven't worked with a laser range finder but
I suspect they use it to narrow the focus onto moving objects to process
video in more detail in those areas.
...
The current buzzword "co-robots" meaning robots that work beside or
cooperatively with people working in symbiotic relationships with human
partners suggests everyone will need a robot friend, which will require an
artificial intelligence capable of intelligent thought.  As most Americans
are Christian it would make sense for a human compatible AI to be based on
the Bible.  That is what I would love to work on.  But that level of
thought needs a creative CG environment like Squeak at present.
...
I've been thinking that using a Smalltalk GUI to issue command rules to
set an agenda for automatic text analysis and editing might be fun, letting
the computer do the editing instead of me.  That way it could update the AI
knowledge like when a preferred synonym is discovered, without taking human
time to do much of it beyond the setup.
...
Your wikipedia entry shows a webpage and blog that apparently are dead
links.  Would you be interested in being a team member on my SBIR/STTR
grant application(s) for AI and Robots responding to:
...
http://www.nsf.gov/publications/pub_summ.jsp?ods_key=nsf15505  I've
enlisted help in writing the application from Oregon's Small Business
Development Center and will meet with an SBIR road trip in August I'm
told.  (I was also told I need a Ph.D. on my team since I don't have one.)
...
Kirk Fraser
...
On Mon, Jul 6, 2015 at 4:19 AM, Ralph Johnson johnson@cs.uiuc.edu
wrote:
...
...
Here is another possibility.
Take a look at Symbolic Sound, a company that makes a system called
Kyma.    http://kyma.symbolicsound.com/
...
...
This company has been around for over twenty years.   Its product has
always been the fastest music synthesis system in the world that gives you
total control over your sound.  And by "total", I mean it gives you the
ability to mathematically specify each sound wave.   If you want, which is
actually too much detail for most people.   And it is all written in
Smalltalk.  Not Squeak, of course, since Squeak wasn't around then.   But
it could have been done in Squeak.   And perhaps they ported it to Squeak.
 I haven't talked to them for a long time so I don't know what they did,
but from the screen shots I think it is still a very old version of
VisualWorks.
...
...
Anyway, how do they make it so fast?  How can they make something that
can be used for hours without any GC pauses?
...
...
The trick is that the sound is produced on an attached DSP.   The GUI
is in Smalltalk on a PC, and it generates code for the DSP.   It is
non-trivial making the compiler so fast that when you press "play", it can
immediately start up the DSP and start producing sound.  It does this
(rather, it did this, since they might have changed the way it works) by
just producing enough code to run the DSP for a few seconds and then
starting the DSP while it generates the rest of the code.   Kyma literally
is writing the program into DSP memory at the same time as the DSP is
running the program, producing sound.
...
...
Anyway, maybe that is the right approach to programming robots.   You
don't even need to use two computers.   Imagine you had two computers, one
running Squeak and the other a simple, real-time machine designed for
controlling robots, but not very sophisticated.  Squeak programs the simple
computer, and can change its program dynamically.  The simple computer has
no gc.   Since Squeak is a VM on a computer, the real-time computer can be
a VM, too.  So, you could be running them both on your PC, or you could run
them on two separate computers for better performance.
...
...
I would be happy to talk more about this.  But I'd like to talk about
the beginning of Kyma.   The owners of Symbolic Sound are Carla Scaletti
and Kurt Hebel.   Carla has a PhD in music, and Kurt in Electrical
Engineering.   I met Carla after she had her PhD.  She wanted to get a MS
in computer science so she could prove her computer music expertise, and
she ended up getting it with me.   She took my course on OOP&D that used
Smalltalk.  For her class project (back in 1987, I think) she wrote a
Smalltalk program that ran on the Mac and that produced about ten seconds
of sound, but it took several minutes to do it.   Hardly real time.
 However, she was used to using a supercomputer (a Cray?) to generate
sounds that still weren't real time, so she was very pleased that she could
do it on the Mac at all, and though Smalltalk was slower than Fortran, in
her opinion the ease of use was so great that she didn't mind the speed
difference.   As she put it, the speed difference between a Mac and a Cray
was bigger than between Smalltalk and Fortran.  She ended up turning this
into the first version of Kyma and that became the subject of her MS
thesis.   I can remember when she showed it in class.  She was the only
woman in the class, and the other students knew she was a musician, i.e.
not *really* a programmer.  She was quiet during class, so they had not had
a chance to have their prejudices remedied.  Her demo at the end of the
semester blew them away.
...
...
Kurt had built a DSP that their lab used.   (The lab was part of the
Plato project, I believe, one of the huge number of creative results of
this very significant project at Illinois.)   It was called the Capybara.
This was before the time when you could just buy a good DSP on a chip, but
that time came very soon and then they used the commercial chips.  For her
MS, she converted her system to use the Capybara, and this was when she
figured out how to make it start making music within a fraction of a second
of pressing the "play" button.  Kurt also used Smalltalk with the
Capybara.  His PhD was about automatically designing digital filters, and
his software also generated code for the Capybara, though it was actually
quite different from Kyma.
...
...
The two of them worked on several different projects over the next few
years, but kept improving Kyma.   Along the way Kurt started building
boards that had several commercial DSPs on them.  Eventually they decided
to go commercial and started Symbolic Sound.
...
...
-Ralph Johnson
...
On Sun, Jul 5, 2015 at 9:05 PM, Kirk Fraser overcomer.man@gmail.com
wrote:
...
...
...
...
...
Tim says a multi-core VM is coming for the new Pi.
...
Are you *sure* that's what Tim said?
Of course my over hopeful misinterpretation is possible.
"Squeak runs quite well on a Pi, especially a pi2 - and we're working
on the Cog dynamic translation VM right now, which should with luck triple
typical performance."  - timrowledge » Thu Feb 19, 2015
...
...
...
https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=100804&p=698...
...
...
...
...
The trick to getting rid of long delays is more a function of
preallocating everything you can than getting rid of GC's (I've done some
highly interactive stuff in GC environments and preventing GC's is
impractical except over short periods of time, minimizing their frequency
and duration is very doable)  One of the things I think I
...
...
...
recently saw that should help you in this regard is FFI memory pinning
if you're calling out to external code.
...
...
...
Thanks.  Maybe when I find, make, or build a better place to work,
I'll be able to tackle some of that.  I wouldn't be surprised if a VM is as
easy as a compiler once one actually starts working on it.
...
...
...
...
On Sun, Jul 5, 2015 at 6:31 PM, Phil (list) pbpublist@gmail.com
wrote:
...
...
...
...
On Sun, 2015-07-05 at 17:12 -0700, Kirk Fraser wrote:
...
I used Cuis at first to display hand written G-Codes in graphic form
for a printed circuit board.  I kept up with Cuis through a few
versions and found a couple of bugs for Juan.  Eventually Casey
advised going to Squeak so I did. Perhaps my requests were getting
annoying.
Perhaps you misinterpreted what Casey said?  Definitely have all
options
...
...
...
...
(Squeak, Pharo, Cuis etc.) as part of your toolkit.  Squeak in
particular has a very active mailing lists and you'll find a lot of
existing code to play with.  I personally do most of my development in
Cuis, some in Pharo (for things like Seaside that don't yet exist in
Cuis), and a bit still in Squeak.  They all have their place depending
on your needs.  Given your emphasis on performance, I would think that
Cuis is going to be the place where you can maximize it. (all the
above
...
...
...
...
Smalltalk variants use essentially the same core VM, it's the plugins
and images that really differ)
...
I'm mostly interested in using a multi-core Squeak with GC control
for
...
...
...
...
...
my robot.  Tim says a multi-core VM is coming for the new Pi.  He
hasn't answered on GC control.  With muliti-core a user need not see
GC control but the system should provide 100% GC free service even
if
...
...
...
...
...
behind the scenes it momentarily toggles one GC off and lets the
other
...
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complete.
Are you *sure* that's what Tim said?  I see a thread where he's
talking
...
...
...
...
about *build* performance (i.e. compiling the C code for the VM) on a
quad-core with the caveat 'even if Squeak can't directly take
advantage' (i.e. no multi-core VM)
...
With real time driving, which I hope my robot will do some day,
getting rid of all 100ms delays is vital.
The trick to getting rid of long delays is more a function of
preallocating everything you can than getting rid of GC's (I've done
some highly interactive stuff in GC environments and preventing GC's
is
...
...
...
...
impractical except over short periods of time, minimizing their
frequency and duration is very doable)  One of the things I think I
recently saw that should help you in this regard is FFI memory pinning
if you're calling out to external code.
...
On Sun, Jul 5, 2015 at 4:54 PM, Dan Norton dnorton@mindspring.com
wrote:
        On 5 Jul 2015 at 16:22, Kirk Fraser wrote:
    >
    > We should ask why do people want to teach Python instead

of
...
...
...
...
...
    > Smalltalk?  Why do people veer
    > away from Smalltalk with add-ons like Etoys, Scratch, and
    many other
    > paradigms like Patterns
    > and CRC cards, which aren't as good for commercial
    programming, thus
    > really aren't as good to
    > teach children?  What can be done to remodel Squeak to
    provide all
    > the features more
    > commercially popular languages have?
    >
    > Earlier a post saying a boss didn't want a GUI that a
    combination of
    > buttons would bring up all
    > sorts of things his employees shouldn't be playing with.

So
...
...
...
...
...
    put a
    > cleaner commercial GUI on the
    > list. Maybe the preferences switch could be in its own

file
...
...
...
...
...
    or as
    > the first character in Sources to
    > reduce file count.  The Changes file shouldn't be needed

in
...
...
...
...
...
    a
    > deployed application.  Is there any
    > way to cut the deployment image down to one file

containing
...
...
...
...
...
    both the
    > Sources and VM like an
    > .exe in any other language?
    >
    > I've written on the need to fix Garbage Collection control
    so it can
    > be turned off like Python allows
    > to enable Squeak to be used for real time projects like

self
...
...
...
...
...
    driving
    > cars, since a 100ms delay can
    > veer 8 feet off course, fully into a lane of oncoming
    traffic.
    >
    > Recently I learned from a UC Berkeley website it takes

100ms
...
...
...
...
...
    to
    > recognize the objects in a
    > picture too.  Does that mean the future will have a cloud

in
...
...
...
...
...
    every
    > car and Squeak needing to
    > conduct image analysis in hundreds of cooperating cores to
    get safe
    > real time performance?
    >
    > The state of Squeak for all its benefits seems like a
    collection of
    > law statutes, a big set of text
    > contributed by years of legislation that nobody can

remember
...
...
...
...
...
    all of
    > and some of which makes little
    > sense.  Maybe a major rewrite starting from zero would

help?
...
...
...
...
...
    >

    " like a collection of law statutes" is a good analogy. Cuis
    seems like a major rewrite of Squeak and is simpler, easier

to
...
...
...
...
...
    understand. What do you think of Cuis?

    > The GUI - while it has many nice features, it somehow

seems
...
...
...
...
...
    to lack
    > the crisp precision, ease,
    > and speed of commercial software like Solidworks.  I like
    how
    > Squeak comes up and is ready to
    > go far quicker than say Amazon's Audible application but
    Squeak
    > graphics aren't so fast or easy
    > to program as Solidworks.
    >
    > Recently I saw a couple of short videos on two moderate

size
...
...
...
...
...
    robots
    > where users extolled their
    > ease of programming.  Perhaps Smalltalk needs a new top
    level rule
    > based language to improve
    > programmer efficiency.  I'm working on this one.  And as

my
...
...
...
...
...
    > prototype was so easy, it angers me
    > to think of all the time I spent being both ignorant and
    afraid
    > after seeing various compiler books
    > like the "Dragon Book" intentionally make compiler

writing a
...
...
...
...
...
    > difficult graduate level course instead
    > of an easy advanced beginner level assignment.
    >
    > But one thing I have in common with my Raspberry Pi, when

my
...
...
...
...
...
    > utilization is maxed for too long, I
    > overheat and shut down.  I can write simple stuff like

this
...
...
...
...
...
    when
    > it's too hot to do real work.  But
    > even multiple cores get too hot when they are maxed out.

So
...
...
...
...
...
    a real
    > time computer needs heat
    > control or cooling overkill in case a vital complex
    situation clogs
    > the bandwidth.  Well, pray about
    > it.

     - Dan

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[Newbies] Re: Beginners Digest, Vol 108, Issue 5