Up until recently I was a bit fuzzy on the difference between concurrency and distributed systems.  It was not until I was studying Facebook Chat, Erlang, Scala, Go, and the new python web server Tornado that it finally clicked.  Concurrency simply implies that two or more pieces of code are executing at the same time.  Distributed system are running concurrently on many different machines.

The difference is a critical when planning how to scale a system.  With simple concurrency, you can only scale a program vertically- by adding faster or more cores, installing more ram, etc.  However, a properly abstracted distributed system can be scaled horizontally – adding in more machines or nodes to the system easily by simply modifying a config file.

Scala and Erlang and Google’s new language Go share a model of concurrency based on message passing.  However, only one of these languages, Erlang, natively supports distributed systems using its message passing system.  Erlang’s native and transparent support of distributed computing is one of the reasons Facebook chose to use it for Facebook Chat. Other languages like Scala and Python require cumbersome third party libraries to support distributed computing.  Scala’s lack of native support for distributed computing is particularly interesting given that it’s concurrency model is directly based on Erlang.

So I could learn Erlang, or try to learn distributed programming in Python. It has tons of third party options for distributed programming, but as yet I don’t know which is the best.

Thoughts? Am I an idiot?

PS: Thanks to my six readers Jeff, Thor, Karan, Eric,  Rachel, and Dad for reading!

EDIT:

And Jamie (Nice blog dude! (Omegle Voyeur is hilarious))

My next coop position will be with Amazon.com in Seattle from January to April 2010.  I’m excited and a bit nervous to be working at Amazon!  Getting this kind of coop position is one of the major reasons I chose Waterloo and the Software Engineering profession.  Hopefully the job lives up to the hype and I live up to my own expectations of excellence.  I’d like to talk about what I’ll be doing over there, but I’m under a strict NDA.

I am sitting in ECE 126, Electricity and Magnetism.  I’m not paying attention (clearly because I’m writing this). This class is useless for a Software Engineer. Ordinarily, I am entranced and fascinated by advanced science, but calculating the voltage or capacitance of a complex circuit system is of little interest to me. Perhaps if we learned how these equations are derived class would at least be interesting – if not still useful for my degree.

It pains me that seemingly only one or two classes I take each term is relevant to Software Engineering. This term it’s CS 241, which is by far the best class I’ve taken in my program thus far.  I’ve actually learned many interesting CS concepts, such as the origin of regular expressions in DFAs, MIPS assembly, and how to write a functioning assembler.  Thankfully, I’ve been informed I will have more classes of this quality in the future (hopefully).

It would be useful for a class on data structures and algorithms to be included in the 2A curriculum.  I independently studied graph theory in preparation of my interviews this semester and let me just say it was a good thing I did!

Finally, a tip for those who watch How I met your Mother and The Big Bang Theory.  Watch TBBT first, because the superior writing in HIMYM tends to ruin TBBT if watched second.

So maybe I don’t write a ton of blog updates… but I do use Twitter now!! http://www.twitter.com/andrewmunn

This Wordpress theme is gorgeous!  Checkout the Javascript rollover effects on the links on the left! Snazzy.

Greg Burgoon is a Waterloo Computer Science student in his final year.  He is a colleague of mine at Xtreme Labs and has agreed to write a post on my blog.  Take it away Greg!

“So, I was sitting today, thinking ‘Man, i feel like writing….’ and BAM, Andrew was like ‘I’ll let you do a guest post on my blog’.  So here I am.  So we’re doing Palm Pre development, and let me tell you….its garbage…..but fantastic…….at the same time.   Due to the nature of webOS, palm is very easy for web developers to get started on (or any developer, cuz let be honest, web development is easy), but because it is based on javascript it limits your capabilities (ie. hitting a server via ajax and retrieving a large file can kill your phone ). Also, I like long walks on the beach.  And in true  5 year old writing style, here is the end of my post. THE END.”

Thanks Greg for the insightful, ground-breaking, and frankly riviting commentary.  Finally, here is a picture of the coolest person I’ve ever met.

Andrew is one badass dude.

My blog is up and running after been down for a while. I’m now hosted on NFS, which charges by the bandwidth and HD space used, so don’t comment too much .

Unfortunately many of my older posts have encoding errors which have added random characters. This is the result of a database dump mistake. On the bright side, nobody read’s my posts anyway, so no loss to the world.

I shall write a post comparing developing for iPhone,  Palm Pre, Blackberry, Android, and Symbian soon.  Who knows, I might make it actually good and try to get on Reddit!

At my coop job this summer I’ve had the pleasure of developing mobile applications for the Android, Blackberry, and Symbian platforms.  The contrast between the three from a developer’s point of view is striking, especially for me because I ported an application between all three.

The first platform I was introduced to was Google’s Android.  Android applications are written in Java.  Blackberry and Symbian are written in Java ME. What’s the difference?  I’ll illustrate with a few problems I experienced and the solutions I used.

Problem 1: I need to remove HTML tags from a string.

Android: I’ll either use a simple regular expression or the tag remover method that comes with Android.

Java ME: I’ll either write a crappy HTML remover by hand or find and install a 3rd party regex engine.

Problem 2: I need a GUI element that smoothly animates between a bunch of pictures. (A picture gallery)

Android: I’ll use the built in gallery widget.

Java ME: I’ll spend days writing my own gallery widget at a low level or pay to use a 3rd party GUI toolkit like J2ME Polish.

Problem 3: I need to format the output of some floating point numbers to 2 digits after the decimal point (ie, money)

Android: I’ll use the String Formatter class that comes with Java.

Java ME: I’ll be shocked that simple output formating that has been available since C was released is not available in Java ME. I will  then I’ll spend 90 minutes formatting my output with if statements.

Problem 4: I need to sort an array of objects.

Android: I’ll have the objects implement Comparitor then I’ll use the built in Array sorting method.

Java ME: I jump off a cliff.

Problem 5: I need to store some user data

Android: I’ll use the built in SQLite DB or, for simple app settings, I’ll use a persistence dictionary.

Java ME: I overdose on cocaine.

You get the picture.

The blog has been down for over a month now, thanks to Karan deleting my wordpress installation and me being too busy (read: Lazy) to fix it.   However, it’s back!  Expect updates on Android, Blackberry, and Symbian development.

Algebra 135 exam was yesterday.  It went well, although I messed up what should have been a straight forward proof.  Macro Economics exam is in a few hours, and I’m still procrasting from studying by writing this post.  Computer Science exam is tomorrow morning.  I’m not terribly worried about that one, although I haven’t programmed in scheme in a few months.  I hope the test is mostly C++.  On Thursday I’ve got calculus, which will be difficult, but I’ll be ready.  Then next week it’s Digital Circuits and Management Science.  Those should be interesting because I stopped going to classes sometime after the midterms.  I’ve got a lot of catching up to do .

If you’re bored, spend some time at Star Trek Tweets, my newest creation!  It’s an experiment in using the Twitter API and making cross-domain AJAX calls.  No server-side code required!

Also, putting Google AdSense on Find the Hotties as made me almost $1 so far.  Awesome! (well, 50 cents because I suppose I should give half to Noah).