Tech Blog

To install ffmpeg via homebrew you need to specify which compiler to use on 10.7 at least:

Cheers, Mark

Learnosity develops cutting edge tools for language learning and is used by the leading educational publishers and assessment companies globally. We deliver millions of assessments every year, to users on 6 continents.

We are looking for multiple roles from junior to mid level range.

Read the rest of this entry

Learnosity develops cutting edge tools for language learning and is used by the leading educational publishers and assessment companies globally. We deliver millions of assessments every year, to users on 6 continents.

We are looking for multiple roles from junior to mid level range.

Read the rest of this entry

Learnosity are looking for a DevOps/Linux Engineer to join our growing team.

Note: this role has now been filled. Thanks to all who applied.

Learnosity is an award winning company which develops cutting edge tools for language learning and is used by the leading educational publishers and assessment companies globally. We deliver millions of assessments every year to users on 6 continents.

Read the rest of this entry

For a recent project we wanted to use Railo encrypted DSN's passwords in the railo-server.xml.

The only issue was that the encryption of the passwords was not documented as to how it works. A bit of digging around in the source code showed me how it was done and I've now made a simple page that will generate these encrypted passwords.

Benefits: - Can use encrypted passwords - Don't need to be able to see the production DB when creating the config file

So I can now generate encrypted passwords for railo without hooking my laptop railo instance up to the production db's. Nice.

I've been updaging our existing documentation which was written in AsciiDoc and also creating new documentation recently.

Our normal process is to update the source text file, commit to our SVN and the run the documentation build script from the deployment server to create the HTML and PDF versions of the document.

This works fine from our server but to speed things up while I was writing the documents and make sure I had the formatting correct I thought I'd install AsciiDoc on my laptop and 'build' the document locally before committing to SVN, building and checking.

Installing AsciiDoc is simple enough using MacPorts:

Creating a html version of your AsciiDoc is simple at this point:

That will output a file called sample.html in the same directory as the source file. No worries ...

To create a PDF or an ePub, it's recommended that you use the a2x command instead of asciidoc though.

According to the AsciiDoc website "a2x is A toolchain manager for AsciiDoc (converts Asciidoc text files to other file formats)"

So I gave this a try:

It generated the following error though!

It took a bit of Googling (sp?) but I found the core of my solution in this post:Fixing the ePub problem with Docbook-XSL/A2X/Asciidoc

The only 'tricky' part was finding my catalogue.xml, which ended up being in /opt/local/share/xsl/docbook-xsl ... and I modified the contents to be:

Once I had done that, everything generated fine :)

The next thing I need to work on is getting the default XSLT template cleaned up :)

HTH

A.J.

The main answer on the web is: Increase the size of you permgen by adding the following:

However, to me this just delays the problem, particularly if you are using dynamic languages which load a lot of classes eg Railo.

So a bit of further digging found these options:

These 3 options allow the permgen memory to be garbage collected. I tried to find a good reference link for them but couldn't.

The final thing that I discovered was the jmap tool - which is very helpful for understanding the memory usage.

You run it as follows and it gives a great summary of the memory usage of your running jvm.

Cheers, Mark

Getting Setup

Here is some documentation for reference and to help others:

1. Get the SDK from Amazon

• I got version 1.2.4 from here: http://aws.amazon.com/sdkforjava/
• Extract the lib/aws-java-sdk-1.2.4jar file and put it in your tomcat/lib folder

2. Get the HTTPComponents Client

• You will also need get the HTTPComponents Client from apache as it depends on this. http://hc.apache.org/downloads.cgi I downloaded the 4.1.1 release and this worked a treat
• Extract the 6 jars and drop them in your tomcat/lib folder.

3. Restart Tomcat and write some code

Comparison of techniques

I played with a few different techniques of using the AWS with tomcat and found the following:

1. CFHTTP direct API calls

2. Java AWS SDK from Railo

This worked well, but each request took on average of 1500ms from AU to US East AWS. This was disappointing, so I tried caching in the the application scope as below.

3. Java AWS SDK cached in App Scope

The first request took ~ 1500ms but then subsequent requests were about 300ms, which was 1/3 of the time of the raw CF code. With the added benefit of having full access to all the API's, this is definitely the way we'll be using it going forward.

Cheers, Mark

References

• AWS Java SDK reference
• List of endpoints for each Amazon service

Learnosity develop cutting edge tools for teachers and educators.  Our flagship product Learnosity Voice uses the telephone to enable language students and teachers to interact on a one to one level.

Our service:

• Makes it practical for students to practice Oral and Aural skills.
• Is efficient and effective for teachers, as they can listen to each student individually at a time to suit them.
• Can be used for homework assignments or “High Stakes Assessments”.

Learnosity are creating the next generation of language and assessment technology for use in schools and education worldwide.  The current product portfolio includes:

• High availability web based systems.
• Cross platform software platforms (Windows, Mac and Linux).
• iPhone/Android native applications.
• VOIP and SMS applications.

We need someone who can:

• Use Javascript or Actionscript to create great user interfaces.
• Develop highly scalable web applications using ColdFusion, PHP or similar.
• Cut code with the best in the world.

You will also need to be:

• keen to continue learning new technologies.
• able to have a conversation with non technical people.

You'll need:

• 1-3 years of programming experience.
• Expert in at least one Client side language (Actionscript or Javascript/jQuery).
• Experience in at least one Server side language (eg PHP, Java, ColdFusion, etc).
• Understanding of Object Oriented design.
• Understanding of XHTML and CSS.

It would be good if you have:

• a degree in Computer Science, Engineering or similar.
• been working with open source tools.
• been playing around with iPhone/Android applications.
• experience with some of Linux/VOIP/SIP/Asterisk/Jabber/XMPP.

This is a full time role and you will be working in a casual workplace with flexible hours in the Sydney CBD.   Salary commensurate with experience.

If this sounds like the job for you, email a covering letter explaining why you'll be great and your resume to mark.lynch[at]learnosity.com - no agencies please. 

The message they got was:

I knew that the site and file were both available and a bit of hunting around I was reminded that IE used to have issues with Gzip encoding in the past - but I presumed that it was a thing of the past.

I also noticed that when downloading the file Firefox would not show a progress bar but would instead show a "indeterminate progress" bar.

Looking at the headers the it turned out that there was no Content-Length header but there was a header as follows:

To fix this I added some more exclusions to my mod_gzip rules to not zip some particular file types.

Now its working a treat. It would also be possible to do this only for IE - but most of the files we use on this are already well compressed to gzip compression doesn't help too much anyway.

Cheers, Mark