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Generating prime numbers with Erlang and Java
Jens' Blog - 6 August, 2009 - 14:17
During my work with the course-ware of a new Erlang course, I experimented with one of the programming assignments to compare the threading performance of Erlang versus Java. The assignment is one of the classical programs from teaching concurrent programming: How to generate prime numbers using a pipeline of sieve ...
The critical section problem in Erlang
Jens' Blog - 6 August, 2009 - 14:17
The programming language Erlang is based on micro-threads and asynchronous message passing. There is a (naive) belief that critical section problems cannot arise in languages based solely on message passing. The justification for this stand-point is the absence of mutex synchronization primitives, which is absolutely essential in shared-data based concurrent ...
The ups and downs of Erlang
Jens' Blog - 6 August, 2009 - 14:17
I just finished reading the paper A History of Erlang by its inventor Joe Armstrong. It's really a fascinating story and I can really recommend reading Joe's own words regarding the invention and development of the language. Back in the late 80's and beginning of the 90s I spent some time ...
Introscope extensions
Jens' Blog - 6 August, 2009 - 14:17
Back in January 2005 I joined an existing San Francisco based company named Wily Technology. This was the beginning of a few years of hectic traveling, hacking and trouble-shooting. Meaning I traveled around in Europe, mostly UK and Germany, working at customer sites (some very large banks) helping them with ...
New organization of RiboUtils
Jens' Blog - 6 August, 2009 - 14:17
When re-launched Ribomation in April this year I hastely re-organized the web site as well, moving this blog into blog.ribomation.com and setting up the new 'corporate' site using Drupal. Something I (intentionally) left for a later time was making a new home for RiboUtils, my over the years collection of ...
Video from my Cloud Computing seminar
Jens' Blog - 6 August, 2009 - 14:17
This week I gave the same seminar regarding "What is Cloud Computing" in both Stockholm and Göteborg, here in Sweden. You can watch the video from the Stockholm event. The speech language is in Swedish and the length is around one and a half hour. The video format is Adobe Flash, ...
Comparison of decompress ways in Hadoop
Jens' Blog - 6 August, 2009 - 14:17
I have recently made some programming using Hadoop, which is a framework for massive data processing over many numbers of servers. Hadoop reads input data from (large) files and performs MapReduce data reductions. One method of reading is input is decompressing GZIP:ed files. Java has built-in support for reading gzipped stream ...
I’m (re-)launching Ribomation
Jens' Blog - 6 August, 2009 - 14:17
During the 90s I was running my own company Ribomation, devoted to training (and consulting) in advanced software development areas. In the beginning it was mostly C, C++, OOAD and threads programming in Linux. Towards the end of the 90s, it was Java only - all sorts of Java related ...
Using TMI instead of Actors
Jens' Blog - 6 August, 2009 - 14:17
Here in Sweden the spring has finally arrived and one of the duties I have to do is switching from winter to summer tires on my car. I did that this morning and while waiting in the garage I was reading the two articles about Actor concurrency in JavaWorld. The ...
Scala seems to be fun
Jens' Blog - 6 August, 2009 - 14:17
The second day of Jfokus was an ordinary conference day, with separate tracks and many talks to choose between. JavaFX The key note talk at the beginning described JavaFX, SUNs new "SilverLight and Flash" killer. The demo showing how to flip through a book with very realistic behaviour, was impressive. On the ...
WebSockets is the way forward of pure web applications
Jens' Blog - 6 August, 2009 - 14:17
Today I attended the first day of the two-day JFokus conference in central Stockholm. In just three years it has become one of the major Java events in the Scandinavian region. The first day was composed of two half-day sessions. I decided to go for websockets before lunch and performance ...
How to jump into the Cloud
Jens' Blog - 6 August, 2009 - 14:17
Cloud computing is a general term for a public accessible virtualization system. Virtualization + DataCenter + PublicAccess = CloudComputing Although there are more than one provider and others to follow, Amazon (AWS) has pioneered the field and I will refer to AWS only when describing hands-on procedures. Sign Up The first thing to do ...
What’s in the cloud?
Jens' Blog - 6 August, 2009 - 14:17
Nowadays, there are many services provided by Amazon WebServices (from now on referred to as AWS). Names and acronyms such as S3, EC2, SQS, FPS, SimpleDB, CloudFront, EBS, EIA are swirling around. I intend not to describe all of these, rather I will concentrate on the second acronym; EC2 (Elastic ...
Into the Cloud
Jens' Blog - 6 August, 2009 - 14:17
I have previously investigated virtualization. A few years ago I used VMware WorkStation to run Fedora and Ubuntu on top WindowsXP. And before last summer, I used WMWS for a customer project running a deskop Ubuntu and two server Ubuntus (one with Oracle and the other as the project server). ...
New job
Jens' Blog - 6 August, 2009 - 14:17
Next week (1st December) I'm switching to a new job for Connecta, which is a consultancy company in central Stockholm. My role will be to lead and build up the Java knowledge of a team in the area of Enterprise Java.
A first look at Spring-Batch, part 2
Jens' Blog - 3 August, 2009 - 20:17
In my first post about Spring-Batch, I described in detail a Hello-World application using Spring-Batch and discussing the necessary plumbing wiring needed in the spring-beans configuration file. In this second post I will take it one step further, by introducing the concept of tokenizer and field-set mapper. I will copy-reuse as ...
A first look at Spring Batch
Jens' Blog - 15 July, 2009 - 14:17
Spring-Batch is a rather new project within the Spring portfolio. It addresses a large field within computing, although not main stream in Java. A lot of corporate computing is managed by batch processing, many business transactions based on file input picked up from FTP drop zones etc. Back in 2003, I ...
The Camel Distribution
Jens' Blog - 1 July, 2009 - 19:17
Long time ago, before the internet era, I was working on my PhD in the field of distributed event-driven simulation. One of the key questions was how to manage the event time line. The pitch in this case is that the time line is distributed. To be more precise; a simulation ...
