Đánh giá nhanh màn hình LCD Dell S2740L: 27", IPS, đèn nền LED Full HD, giá 8,25 triệu

Hiện nay, màn hình LCD gần như đã hoàn toàn thay thế được công nghệ màn hình CRT cũ, bởi những ưu điểm vượt trội mà nó mang lại, như kích thước lớn hơn trong khi lại gọn nhẹ hơn, màu sắc tươi sáng và đặc biệt là ít tốn điện hơn nhiều lần.

Kết quả kinh doanh Quý 3 của Dell: lợi nhuận đạt 475 triệu USD, giảm 47%

Mới đây Dell đã công bố kết quả hoạt động kinh doanh Quý 3/2012 của mình. Theo đó, lợi nhuận trong 3 tháng vừa qua của hãng đạt 475 triệu USD, giảm 47%

Windows Phone 7.8 đã hoàn chỉnh, có thể được phân phối trong vài ngày hoặc vài tuần tới

Nokia và Microsoft vừa tổ chức một sự kiện dành cho các lập trình viên tại Singapore vào ngày 17/11 vừa qua, trong đó nhất mạnh đến việc phát triển phần mềm cho Windows Phone 8.

Tuesday, 21 September 2010

How to build a BeagleBoard-based Open Source Ebook Reader

Ebook readers were hailed several months ago as the end-all-be-all of digital devices. They were supposed to put books out of business. In effect they have, they've put some book distributors out of business. But somehow, the Ebook itself is somewhat unsatisfying - after all the hoopla, we're left with "just" a screen tablet-like device, with a few buttons and a mini keyboard. It just doesn't feel like there's enough new to it... so I got inspired to build my own as a platform for experimenting with the "user experience" of Ebooks.

I got bored with my Kindle after about 20 times using it, and started wanting to hack it. I have a modern form of A.D.D. that makes me want to break open cases and solder memory expansion ports onto any device I touch. There's so much I'd do differently, yet you can't really do any development on it - I don't understand - they should just open it up, and let people like me hack away at it.



Since Amazon didn't, and doesn't, I decided to turn the Open SciCal into a hackable ebook reader, based on the FBReader source code. This means that it's hackable from the ground up...


It's not bad, but there are some things I'd change. Luckily I can, because the source is open and accessible... in fact, it's quite easy to understand - here's the important main function set, from FBReader, which gives a good idea of how approachable the code is (if you know C and C++, that is):



void FBReader::openBookInternal(shared_ptr book) {
    if (!book.isNull()) {
        BookTextView &bookTextView = (BookTextView&)*myBookTextView;
        ContentsView &contentsView = (ContentsView&)*myContentsView;
        FootnoteView &footnoteView = (FootnoteView&)*myFootnoteView;

        bookTextView.saveState();
        bookTextView.setModel(0, 0);
        bookTextView.setContentsModel(0);
        contentsView.setModel(0);
        myModel.reset();
        myModel = new BookModel(book);
        ZLTextHyphenator::Instance().load(book->language());
        bookTextView.setModel(myModel->bookTextModel(), book);
        bookTextView.setCaption(book->title());
        bookTextView.setContentsModel(myModel->contentsModel());
        footnoteView.setModel(0);
        footnoteView.setCaption(book->title());
        contentsView.setModel(myModel->contentsModel());
        contentsView.setCaption(book->title());

        Library::Instance().addBook(book);
        Library::Instance().addBookToRecentList(book);
        ((RecentBooksPopupData&)*myRecentBooksPopupData).updateId();
        showBookTextView();
    }
}



The Open Source Ebook reader is based on a handful of modules:

-BeagleBoard - the guts of my Ebook uses the TI OMAP
-BeagleTouch - it has a touchscreen OLED screen
-BeagleJuice - it's powered for 8 hours at a time with lithium ions
-FBReader - open source software, quite nice and hackable
-Liquidware Ebook Boot - an open source boot SD card with a tweaked version of Angstrom to integrate all the parts

The base parts are pretty straight-forward, they just snap together and go. If you're a hacker, you could build it all together pretty straightforward-like from source and use Angstrom. But if you're lazy, you can just buy the "Ebook Boot" SD card which took Chris and Will and me about 2 weeks of hacking around to build, from source, from scratch. It includes all of the drivers needed to get the touchscreen working within Linux, and a handful of libraries and scripts to make wifi, power management, screen control, etc. work right out of the box...


The fully combined stack of modules makes an Ebook:


Here it is from another angle, against a go table that I built by hand (those lines took forever, and were done with a heat iron, for wood carving, but it was so worth it):


This photo is probably the most "ironic" given it's a shot perhaps the most purpose-built hackable Ebook reader on top of the perhaps the most purpose-built non-hackable devices ever: a Mac laptop.


This is probably my favorite picture:


I haven't tried it yet, but conceivably, it could be connected to the net using the Wifi module, and then it could download Ebooks and free Ebooks from the various online stores that FBReader lets you connect to...

I've uploaded some pictures over on the flickr page, and the modules and finished EbookBoot SD Card are all available over at the Liquidware shop... I think I should run a timed contest against myself on how many different types of gadgets I can build within 4 minutes, like these guys that Make blog featured a little while ago...


:-)

Monday, 20 September 2010

I'm heading to Maker Faire NY!

This week is Maker Faire New York City, and it holds a special place in my heart, for a number of reasons. A large part is because Maker Faire is where I started out, 3 years ago, with my humble little TouchShield Legacy and Arduino. At the time, I was traveling quite a bit for my day job, and barely had time to sit in one place long enough to do any serious development.


Maker Faire 

New York
September 25, 26 2010

Fast forward to the present - now I live in Boston, and after three years of driving or flying myself out to San Mateo for Maker Faire's, I'm pretty excited to have one in my own back yard... relatively speaking, that is.

In the past, I've set up tables with some of my favorite hacks. But this time, I'm going to be joined by Justin, Will, and Francis, fellow hackers at Liquidware. And instead of showing off only just my Open Source Hardware hacks, all 4 of us are going to bring along demos and hacks using the latest gadgets.

And at least one of the projects hasn't really been blogged about, because it's still in demo form. Dun dun dun :-)

Ok, back to packing for a busy week ahead...

Sunday, 19 September 2010

Book burning post mortem: digital destruction

Lately I've been reading Joseph Schumpeter's writings on Creative Destruction, in preparation for the upcoming Open Hardware Summit this coming week. I know, some heavy stuff... So my head has been thinking about destruction and acts of purposeful damage.

I've gotten a handful of funny emails and comments in conversations over the past few days in response to my article about book burning, so I thought I'd give it a quick summary of my favorite additional ideas. Far be it from me to beat a dead joke any further than it needs to go (not really, I do it all the time), but I do think there's something worth contemplating here, about the future of book burning.

The essence is: digital desecration is far more nuanced than book burning. You simply have more options to be obnoxious.

In no particular order:
  • Burning isn't good enough, you also have to explicitly destroy some of the content
  • There is a close relationship between desecration and information defacing
  • Digital desecration opens up a more complex relationship between destruction of the physical object, the file, the creative medium, the idea, and the ideology
  • In the digital desecration world, each of these are explicitly different stages (in that sense, is book burning in the traditional sense more effective? will we one day pine for the good ol' days when book burning was as easy as applying incendiaries to paper?)
  • A corollary is that the more creative effort that went into a work of art, the more "satisfying" it is to desecrate (e.g. destroying that which took seconds to build is somewhat lame)
  • A further corollary suggests the ratio of time invested in desecration should somehow be far less than the time someone else invested in the act of creating
  • At the ASCII level, digital defacing might include something like taking a concept or idea, and overwriting or padding it with the word "sucks"
  • At the byte level, you could swap the Endianness of the double chars in order to make it unreadable by whatever chip it's on
  • At the binary level, you could AND or XOR the binary with a random binary sequence, in order to truly make it obfuscated and irretrievable (thanks Devlin)
  • At the file level, you could overwrite pieces of text with strategically identified counter-points or antithetical topics
  • At the archive level, you might rename the cover or title of the file to something misleading, in order to deceive the next potential reader
  • At the chip level, you could create a mechanism that actually made the chip on which bytes were stored burst into flames, moving into the real physical world for some tangible destruction (thanks Chris)
  • At the web level, you could Google bomb the concept or title of the Ebook or text, so that when it's Googled, other links come up at the top that are actually propaganda for something else
  • You could try to measure the performance of desecration by converting electron energy into mass using E=mc^2
  • Less heat is generated from digital desecrations, implying less "wasted energy", and instead there is a more efficient thermodynamic transformation, directing more energy at desecration than being lost as radiating heat
In closing, I'll just throw this out there, since it really got me thinking... we look back on the burning of the Library of Alexandria as a horrible thing, because of all the timeless works of literature that were lost. Do you think anyone would notice if Twitter turned off it's saved tweets archive feature? Will uber-nerdy future historians 1,000 years from now lose cryogenic nano-sleep over this, as they zip around on intergalactic hoverboards?

Probably not.

Wednesday, 15 September 2010

Book-burning needs to modernize

To make things perfectly clear: I do not recommend emotional book burning. I think it's wrong and inefficient. I'm simply going to say this: If you're going to do "book burning" I believe you need to find a more modern way to achieve your goals. Use technology. Better yet, use Open Source technology to achieve your goals.

Something about the press release events of the past week or so has rubbed me the wrong way. But not because of the reasons already expressed by the "media". It's because the guy in Florida is doing it all wrong. We live in a world with headlines filled with stories about Barnes and Noble and Borders books going bankrupt or being sold. Ebooks are taking over. Who can afford to think about burning books at a time like this?
 

In order to have a serious book burning, there's a serious time investment. You'd first have to find the book you wanted to burn, order copies from 10 different retailers on Amazon, pick the most worthy copy, and then commence burning. You'd probably use some social media site to send out Evites or set up a Facebook event hoping people would pull themselves away from Farmville long enough to sit around watching a book burn. What a pain in the rear. If I think about some of my friends, I highly doubt that a book burning event would even hold their attention for more 30 seconds before they were checking their iPhones and Android phones, or sending email on their Blackberries.

When is book burning ok?

If I were homeless in the winter, in a cold climate, and had no other source of shelter, but had plenty of books and matches, I would hope people wouldn't judge me if I were to burn the books I had collected. Alternatively, if I were filming a movie about World War II, or a documentary about a time when books were burned, for historical accuracy, I hope people would appreciate that as art. I suppose if I were the author of the books, it's ok to burn them.

This last reason is cause for serious suspicion. It supposes that there is a relationship between the intellectual property and creative process of writing, authorship, and acceptability of burning books.
 

What happens when you burn books (or blogs)?

Books are actually not so easy to find that I would actually be willing to burn, so I'm burning something closer to my heart. But first, this is me burning a set of blank pieces of paper:



No emotion. Some heat felt. Fire consumed 3 sheets of paper within 62 seconds, for a rate of 2.90 pages / minute.


It wasn't easy finding books I was willing to burn, mostly because I like to take notes in the margins, which I find useful. So instead, this is me burning a recent article from the Antipasto Hardware Blog:

 
EMOTION!!! Some heat felt. Fire consumed 4 pages within 1:48 at a rate of 2.22 pages / minute. The pages were printed with 1622 words across 189 lines, or 7750 characters.


Another way to say this is, my book burning experiment consumed 143.5 bytes / second.


I'm going to assume that the way I folded the paper to allow oxygen in had more to do with the rate of burn than factors like wind (there wasn't any), flammability or not of the ink, or perhaps because my writing is so bad, it burns faster because thermodynamic principles are trying to undo the entropy I create.

What's the difference?

Thought Experiment: Why do people burn books?

I believe that books are burned for several reasons, not limited to the following list:

-Heat
-Light
-Waste disposal
-Publicity leading to social unity
-Desecration

I'll address each one in turn:

-Heat. Not great support for burning books. Modern heaters are known to be more efficient. Plus burning books isn't the quickest, easiest way to generate heat.
-Light. Also not great support for burning books. LED lights are a much more efficient way to achieve this.
-Waste. So so. Just throw it in a landfill, or plant it at the base of a tree to fertilize it. Burning many books, however, may save the time and energy to lug them all to a landfill, so it's a toss-up here for me.
-Publicity leading to social unity. Probably a toss up. This is a lot of effort, and you likely have to create significant consternation before you'll get noticed in the mainstream press.
-Desecration. Now this, I think, is the important point.

Measuring Book Burning Performance: Desecrations / Second

Steve Jobs would probably burn the second volume of my book. Because it's all about Open Source Hardware Strategy and Economics, like what Google uses. Steve hates Open Source, Google, and things that are Open Source like Android, so it's understandable that he might seek to desecrate ideas associated with them.

But here's the problem: if you're going for desecrations, why settle for mediocrity? Why not go all out and desecrate in a modern, digital way?

Here's some Arduino code I wrote to do desecrations:


void setup() {               
  pinMode(13, OUTPUT);    
  Serial.begin(9600);
}

void loop() {
 
  Serial.println("Start");
  Serial.println(millis());
 
  for (int j=0;j<=30000;j++){
  char a[] = "Open Source Hardware is the future.";
  for(int i=0;i<=strlen(a);i++){
  a[i]=0;
  }
  }
 
  Serial.println(millis());
  Serial.println("Done desecrating 30,000 times.");
 
  digitalWrite(13, HIGH);  delay(1000);
  digitalWrite(13, LOW); delay(1000);
 
}



 

Running this sketch achieves 30,000 digital desecrations within roughly 800 milliseconds. This is an effective desecration rate of 1,440,000 desecration-bytes / second!



This Arduino should be ashamed of itself:




It instantiates an array with a phrase, filled with digital bytes of information, and then deletes it from memory. But it does so in the most desecratory way you could imagine: 1 helpless, bloody char at a time - and not even with civil memory management!? From a programmer's point of view, this is heresay. This is like torturing a person by pulling his fingernails out one by one, like every one of those Saw movies. It's like tearing out the pages of a book one by one, and then burning it. Couldn't you have just dereferenced the array pointer, and left the char array in memory? Or if you have to move on, why not just call memory purge?

Ladder of desecration:
Bad: Buying book and burning it (plain form desecration 101)
Worse: Stealing book and burning it (not participating in the economic incentivization system)
Worst: Stealing book, ripping pages out, then burning (physical acts included)

Likewise, here's the digital ladder of desecration:

Bad: Removing software or deleting an ebook from your device
Worse: Torrenting the software and Ebook, and then deleting it
Worst: Torrenting the software and Ebook, and then deleting it, one character or word at a time

Here's some plain R-code to do the same task:

R
x=readLines("OSHWBook.txt");
x <- NULL;

Eh, not a huge impact on my emotions. But this is a completely different story:

R
x=readLines("OSHWBook.txt");
for(j in 1:length(x)) {

for(i in 1:nchar(x[j])) {
x[j][i]="";

}}

x <- NULL;

Seriously?!?!! Is that middle step really necessary? If you're going to delete something just throw it out. There's no need to iteratively replace bytes in memory - without even a simple purge. That's unnecessary and ridiculous.

To me, book burning just doesn't have the same impact as it did when the scholars looked on as the Library of Alexandria was burned to the ground. But this R code hurts. And it's going above and beyond the call to destroy.

Benchmarking Digital Desecration Performance


One could argue that you could measure the strict word count (which is like page count). You could measure file size in bytes, but that's a proxy for document length. You could measure unique words. You could even measure Shannon complexity of the document.


I think there's an open question, perhaps requiring further research, to examine whether or not it makes sense to count bytes, characters, words, or perhaps on synonyms of a specific trigger word or phrase that is considered "desecratory". Perhaps there is an ontological argument to be made about the distribution of desecratory-capable phrases in a document (does it follow a long tail?).


I would argue you want to measure the entropy of the desecrations, which I will define as: number of RAM instantiations and removals of bytes associated with the topic to be desecrated.

Generalization

So I have established a relationship, which I will put in the 2x2 matrix below:


Implementation

Here's some Arduino code that runs on the Arduino and blinks a red LED every time a desecration takes place.


void setup() {               
  pinMode(13, OUTPUT);    
  Serial.begin(9600);
}

void loop() {
 
  Serial.println("Start");
  Serial.println(millis());
 
  for (int j=0;j<=30000;j++){
  char a[] = "Open Source Hardware is the future.";
  for(int i=0;i<=strlen(a);i++){
  a[i]=0;
  }
  }
 
  Serial.println(millis());
  Serial.println("Done desecrating 30,000 times.");
 
  digitalWrite(13, HIGH);  delay(1000);
  digitalWrite(13, LOW); delay(1000);
 
}


Here's the Open SciCal running desecration.r desecrations script:


 x=readLines("OSHWBook.txt");
for(j in 1:length(x)) {

for(i in 1:nchar(x[j])) {
x[j][i]="";

}}

x <- NULL;



Conclusion

I believe book burning is about the public destruction of intellectual property. In a world over-run with new forms of media, and open source software and hardware, however, we need to catch up with the times. I applaud people for having strong beliefs, but if you're going to desecrate someone's intellectual property or creative works, then do so with a modern toolkit!

And do it with Open Source Hardware, why don't you, so others can share in your destructive acts!

:-)

Tuesday, 14 September 2010

Learning PWM with Illuminato Genesis and TouchShield Slide

With the relaunch of the Illuminato Genesis (which was featured on Make Blog a while back), I figured I'd whip together an app that showed off the what the Illuminato Genesis can do. I've been spending a lot of time with the BeagleBoard recently, and that's clearly a top end type device, but the Arduino and Illuminato Genesis plus TouchShield Slide make a nice gadget at the lower end of the spectrum, especially for smaller handheld apps.




I've wrapped everything up into an app on the Open Source App Store over here. The app includes 3 files:


  1. SoftwareSerial_NB.zip - This should be dropped into folder: hardware\arduino\cores\genesis\src\components\library
  2. TouchShield_Pulsing_Sleep.pde - This is a sketch that implements the PWM duty cycle value to the Illuminato Genesis, using the bling() function
  3. Illuminato_Serial_Bling.pde - Listens for PWM duty cycle value from the TouchShield and controls the virtual bling LEDs on the front of the TouchShield Slide
The Illuminato Genesis has an array of gold-rimmed LEDs on the backside of the board, which can be called using a function in the Antipasto Arduino IDE library called bling(). bling(1) turns the LEDs on, and bling(0) turns them off.

So the first step was to implement PWM light control, which is accomplished with this snippet of code:



/* Software PWM modulation routine */
void pwm_bling(char duty) {
  int duration;

  duration = (millis() - pTime);

  if (duration <= duty) {
    bling(1);
  } else {
    bling(0);
  }

  if (duration >= period ) {
    pTime = millis();
  }
}




Then, using serial communications between the Illuminato Genesis and the TouchShield Slide, the PWM'ing is synchronized so that both boards are pulsing at the same speed. The effect is pretty cool looking, if you ask me. On the one hand, you have real LED's on the back of the Illuminato pulsing, and then you have virtual LED's on the TouchShield Slide's OLED pulsing.


Here's the video:



And here are some other pictures:



Tuesday, 7 September 2010

How to make a BeagleBoard Elastic R Beowulf Cluster in a Briefcase

The BeagleBoard's OMAP chip has some serious computing chops, and this project set out to prove it. Ever since I built the Open SciCal, I've been showing it off to nerd friends of mine (that's another way of saying, if I've showed your the Open SciCal in the past 2 weeks, I think you're a nerd that would appreciate it - ha). Granted, a single Open SciCal is nice. But the real impressive part is the combination of serious floating point horsepower with low power.



I figured I'd do this project to respond to all those people who were skeptical that the Open SciCal had any utility in the modern world. Well... my answer is yes.







I took 10 BeagleBoards and turned a suitcase into a wifi-accessible, on-demand, elastic R computer cluster that runs at 10 Ghz, 40 Gigs of disk, and 1,000 megabits of networking bandwidth. I did this all for less than $2,000, and spent less than 5 hours building it, and now I have a scalable compute resource that is portable, has performance comparable to mid-range and high end servers that cost $15,000-30,000 from IBM or Sun. And better yet, it all runs at 30 Watts. That's less than most of the incandescent light bulbs in my room right now.







I've also made the whole project Open Source, for anyone who wants to replicate it on their own. Personally, I'm going to build another one out of 32 of these suckers, and rent it to the trading firm that bought dozens of Open SciCal's from me in the past couple weeks.





Step 1: Get 10 BeagleBoards



I took 10 BeagleBoards, and used the same standoffs that I use in the Embedded Gadget Pack. I used an offset pattern so they could stack as high as I wanted them to. I built them all the way up to 10, and then decided it wouldn't fit in a suitcase, so I split them up into 2 mini-towers of 5 BeagleBoards each.





Step 2: Buy 3 cheap, low power hubs



I went to Radio Shack (begrudgingly because they sold out to the cell phone man in 2000 and have sucked ever since), since they were the only ones open. I bought 1 wireless router with 5 ethernet ports in the back, and then bought 2 netgear hubs (each had 5 ethernet ports).





Step 3: Wire the "interconnection backplane"



I've been reading old literature about multicore, multi-processor, scalable computer architectures, and they have a funky way of making simple concepts like "network" sound really complex like "Fat Tree Fishbone N-Way Scalable Interconnection Backplane".



Oh so you mean I plugged the two hubs into the wireless router, and then put 4 wires into each of the hubs, and 2 from the router, and connected them to the BeagleBoards with USB-to-Ethernet modules.



Like this:







I have this new mantra that things I read in hefty academic papers are written in language way too fancy for what they're trying to do. I get the sense that this is intentional, to hide the fact that what they researched could be replicated for $2,000 and 5 hours in modern times. I kid, partially. I'm reading papers written in the 1980's and 1990's, when the idea of doing what I just did would have taken a $10,000,000 DARPA grant.





Step 4: Set up the Open SciCal Slave Nodes



Each of the BeagleBoards is running the Open SciCal SD card from Liquidware, with a few notable additions:



-Each card is configured to allow passwordless logins over dropbear SSH

-Each card auto-configures itself to a static IP address

-The cards have a slightly trimmed down set of background apps to make R more responsive



I then replicated the card 10 times, onto each of my SD cards.





Step 5: Build the Power Backbone



This was an easy step conceptually, but a pain to do in an organized manner. So I gave up the organization, and just hacked through it. I took 10 BeagleBoard power connectors from the Liquidware shop (specifically those because they're low wattage). And connected them into two small outlet strips.



I then routed those power cables around and through to each of the 10 Open SciCal BeagleBoard Compute Nodes.



For kicks, I got one of those "kill-a-watt" meters and put it in front of the whole set up, so I could measure how much power the whole thing consumed.







Step 6: Configure the Master



Parallel architecture guys are always labeling nodes "master" and "slave". I think it's some hidden repressed anger at the fact that most of us "nerds" never got picked first for kick-ball and 4-square (the game, not the GPS website) when we were kids. Take that, 2nd grade. Now look who's deciding who's "master" and "slave". Me.



In all seriousness, at this point in the project, I had 10 networked Open SciCal nodes. But no way to issue code to them. So I took out my trusty Ubuntu Linux laptop, and quickly got it to connect to the wireless G router I'd set up to be the master switch for all 10 of the BeagleBoards.



Since the system is running on R, I naturally tried to get some of their default environments running, like Snow, Snowfall, svSockets, and even MPI. But each of those turned out to be serious overkill. Sure, they're easy to use if someone else is installing them for you and you don't have to think about it, but they didn't really get the job done in the amount of time I was willing to dedicate, so I wrote my own scripts.



Here are all of the programs I wrote, in one "app" on the "Open Source App Store".





Step 7: Write Elastic R Programs



I was hired by a company a couple months ago to write data mining algorithms to run on the Open SciCal. Most of them were top secret, but a few were pretty elementary. For instance, one function that is used often in text data mining is a function to extract all capitalized phrases. For instance, Amazon uses this on their website to summarize books with a few phrases.



Here's the R code that extracts the indexed location of any capitalized word in a piece of text:





x=readLines(file("data.txt"));

y=(unlist(lapply(x,function(x){lapply(x,function(x){strsplit(x," ")})})));

z=y[y!=""];

out=which(lapply(z,function(x){grep("[A-Z]",unlist(strsplit(x[1],""))[1],value=FALSE,invert=FALSE)})==1);

write.csv(out,file="out.txt")





This is a piece of code that you'd often want to run against 1,000's of pieces of text at a time, to extract important pieces of information. I wrote this into a program called "upper.r".



I then wrote some "administrative" functions for my homemade Elastic R Beowulf cluster - you can download them here:



"esh" - "elastic shell" - this runs a command on all of the slave nodes, and kicks back the output

For instance: esh "uname -a"



"ecp" - "elastic copy" - this copies a file to the home/root/ directory of each of the slave nodes



"epush" - "elastic data replicate push" - this takes a set of data files in the data/ folder called "1.txt" "2.txt" "3.txt" etc. all the way up to "10.txt" and copies them over to each node as /home/root/data.txt. This is important if you want to parallelize different data across to each of the nodes.



"epull" - "elastic data extract pull" - this does the inverse of "epush" in that it pulls a single file called /home/root/out.txt off each of the nodes, and renames them locally into the "out/" folder as "1.txt" "2.txt" "3.txt" etc. according to which node it came off



A typical session would look something like this:



esh "uname -a"

ecp upper.r

epush data.txt

esh "R BATCH < href="http://en.wikipedia.org/wiki/MapReduce">Map/Reduce". If you wrote about parallel computing in the 1980's, you would call it "Distribute/Evaluate/Collect". If you worked at Wolfram Media, you'd call it "ParallelDistribute/ParallelMap". Or if you hacked on the Cray, you'd call it "LoadVec/ParVec/PopVec". At NVIDIA you'd probably call this "CUDALoad/CUDAExecute". Or if you were the CEO of Amazon, I supposed you'd call it "Elastic Cloud Map Reduce" and then you'd make the programming API really obscure and difficult to develop for, and then charge a god-given arm and a leg to use it.



They all do the same thing: copy data to nodes, run them, and copy the output back.





Step 8: Benchmark and Go!



I wrote a couple of benchmark programs that basically run the upper.r code 40 times on a large chunk of text I downloaded from Project
Gutenberg. The benchmarklocal.sh script runs the test 40 times serially locally on my laptop.



The benchmarkparallel.sh script runs the test 10 times in parallel, then repeats 4 times.





#!/bin/bash

./ecp data.txt

./ecp upper.r

./esh "R BATCH --no-save <>



The results are surprising to me, at least. The punchline is that, on average, the Dual-Core Intel chip takes ~30-35 seconds to complete the tests, while the BeagleBoard Elastic R Beowulf Cluster takes around ~20 seconds.



benchmarkparallel.sh is faster than my top-of-the-line $4,500 Lenovo work laptop running benchmarklocal.sh. Now there are always going to be skeptics saying, I could have optimized this or that, but that's not the point. I built it much faster than I could have normally...





Step 9: Take lots of photos



The sky's the limit. Or rather, the practical limit is my ability to appear socially uninhibited as I bring this suitcase into a conference meeting room, pardon myself as I plug it into the outlet (until I get a battery backup unit), and then run the thing at max speed as I calculate floating point math, and extract long capitalized phrases from anything in the room.







I uploaded the rest of the pictures I took in much higher resolution over on Flickr...




:-)



Enjoy...

Sunday, 5 September 2010

If the Old Spice Man were an Arduino

I worked fairly late last night on one of my projects, so I'm in a silly mood as I type this. Justin just mentioned to me that he built some more Illuminato Genesis boards, and that I should mention that they're now in stock for the first time in months. But that would be boring, so I figured I'd "spice" up the public service announcement... and Chris and I have had an inside joke with Chris that the Illuminato Genesis is the Old Spice Man of Arduinos :-)

The Illuminato Genesis has a lot in common with the Old Spice man:

It's ripped - with 42 I/O pins
It's built - by hand
It's tall - with 64k of memory
And it's suave - with custom LED's

So naturally...

Look at your Arduino.


Now back at me.

Now back at your Arduino


Now back to me.

Sadly, he isn't me.

But if he had 42 I/O pins, and had twice the memory, he could function like he's me.


Look down.

Back up.

Where are you? Your in a lab with wires.


With the Arduino your Arduino could look like.


What's in your hand?

Back at me.

It's an oyster (or 2 shells) with two USB mini B connector cables to interface that thing you love.


Look again.

The cables are now a TouchShield Slide!

Anything is possible when your Arduino is an Illuminato Genesis and not a Duemilanove.

I'm on a horse.

You have no idea how hard it is to find a horse these days. :-)

By now, almost the whole world knows about the "Old Spice Man":

Wednesday, 1 September 2010

The emergence of "instant prototyping" vs. "rapid prototyping"

A couple days ago, I talked about why I liked using and programming modular Linux gadgets. Mike wrote me a long email in response to my comment about "rapid prototyping" vs. "instant prototyping" which I thought I'd share.

With the growing popularity of MakerBot, the reduced transaction costs of interfacing with sensors and digital circuits that the Arduino allows, and the emergence of modular prototyping platforms like Liquidware's Beagleboard-based gadget packs and Bug Labs, it feels like there's been a fairly dramatic increase in single-programmer productivity.

I re-read one of my favorite books of all time, "The Mythical Man Month" by Frederick Brooks. Normally I don't get too excited about dense, heavy, cerebral books that don't have any practical advice unless they teach a new programming language (or algorithm). But in this case, I make an exception, because it's just a decent book that questions the process of engineering.


Well, lo and behold, I decided to amazon around for comparable books, and I discovered that the author has written a new book, which sounded even more cerebral and pie-in-the-sky, "The Design of Design". As an aside, I wonder how much more "meta" you can possibly go. How about: "The Process of Thinking about Writing about the Design of Design" ? I mean, even the Greek philosophers had a limit. (Actually, then you'd need to write a book about a "Formalized Grammar and Metaphysics to Document the Process of Thinking about Writing about the Design of Design.")

At some point, for the sake of humanity, I just hope someone remembers how to actually do something tangible! But I digress. Turns out, I enjoyed the book.

It got me thinking. The Matrix movie got me thinking, as did the movie Inception (actually the 13th Floor did too but fewer people saw that one). So the fact that a book held such high company in my mind as the Matrix, Inception, and 13th Floor is high praise coming from me. Much of the book was focused on the process of designing design processes.

How many designers are too many, how should they work together, how do you organize to solve problems? I had a thought while reading the book: design exists because planning for engineering is an important and valuable step in communication and preparing to optimize problems. This is largely because engineering takes time.

Engineering, or building, or solving problems takes time.

But what happens if you break into a new plateau of productivity? What if that time is reduced significantly?

I've hit a personal plateau and breakthrough in productivity twice. Once in software, once in hardware. The software one happened a few years ago, and the hardware one happened about 2 weeks ago.

Software Productivity

My personal software productivity came when I moved from C programming to purely Perl. I realized that I could write an algorithm faster in Perl, and make a functional program faster, than I could in C. Because of that, I could iterate on the program faster, add new features, in less time. The next bump came when I moved from Perl to R. I could do almost everything I could in C in R, except that R also let me access tons of higher level math building blocks. I became really fast at writing code in R... although it took the code longer to execute, I focused on optimizing the algorithm or the way I wrote a function, as opposed to spending lots of time debugging Perl data structures, or C memory leaks.

The common thread was that R allowed a higher level of functional modularity, but still exposed the lower level functions and data types for me to use when I needed them.

Hardware Productivity

Recently, I've felt similarly faster at building hardware than I used to be. I used to have to write PIC chips into protoboards manually with wires that I stripped and cut myself. Then I got excited about Basic STAMP boards because they let me focus more on the code, and on a few simple digital IO pins. Then the Arduino completely changed the way I thought about accessing sensors, switches, and digital interfaces in general - it significantly lowered the "hardware access barrier" if such a thing exists. In practical words, it let me sit down, and hack the E-Ink screen on the Esquire magazine cover in a matter of hours, rather than days. Now, I'm hacking away on Arduino gadget shields and BeagleBoard Gadget Packs... and the time it takes to go from "I have an idea for a gadget hardware that does XYZ" to actually having one in front of me is measured in minutes.

I think I've found the critical pattern... just like in software, the biggest productivity improvement came as the hardware allows a higher level of functional modularity. I'm interfacing with sensors now, as opposed to I2C buses, so I'm able to build a hardware device even faster using a new sensor, for instance. But the important part is that as the hardware gets higher and higher level, it still gives me access to the basic bit-banging serial and data IO ports and buses, just in case.


Open vs. Closed Design Philosophy

That's the biggest difference in my design philosophy and that of Apple. While Apple *hides* digital IO and obscures interfaces, everything I've ever built *opens* the digital raw interface, and keeps that exposed and really easy to access from Perl, R, and C, even as the modules higher level.

The result is much faster hardware and software development.

As this continues, the time it takes to prototype decreases.

At some point, the time it takes me to prototype a device might reach the time it actually takes for me to just build it anyway.

And maybe that's some new concept or field of "extreme" or "agile" instant hardware prototyping.

...and naturally, this is accelerated by the existence of Open Source Hardware...

Why? Because Open Source Hardware is about lowering design barriers, exposing underlying schematics functional blocks, and the result is that prototyping with Open Source Hardware - in my experience - is orders of magnitude faster than traditional dev kits, and proprietary hardware.

...

Wow. Where did that come from? I suppose this is an example of the kind of high level, head-in-the-clouds type thoughts you walk away with after reading "The Design of Design". I feel like the reading rainbow guy: I recommend that book for any design engineer. I think the kind of design discipline I learned will make me a better hardware hacker - or at least a more efficient one (I wonder if anyone's ever done a study on hacker efficiency?) And the honest-to-goodness truth is that I'm not paid to endorse it. I'm not getting any kick backs (ha), nothing. I simply enjoyed the book, and it made me realize something about my own design process I hadn't thought about before...



Ok, back to hacking hardware, I promise...