This blog article details how a brutal interruption of a write operation can corrupt a whole filesystem and how a journal provides a protection against such incomplete writes. 3.1 Consequences of uncomplete writes When you write a file, the underlying filesystem is actually doing two different kinds of write operations: metadata and data writes. For […]
This article should only give you a little introduction to the hole punching process and not a complete composition of all technical details. First I want to show you why peer to peer (P2P) networks are very important for many Internet applications.One of the most important P2P applications is Skype, originally named “Sky peer-to-peer”, but […]
Many applications store passwords for user authentication. Using an appropriate password hashing algorithm can efficiently protect the stored passwords even when the persisted password hashes get stolen by an attacker. Unfortunately many developers assigned with the task to implement a persistent password storage lack the necessary cryptographical background knowledge to choose a strong password hashing […]
In the second part of this blog series I will introduce you to the terrible world of touch event handlers and working around mobile Safari’s behavior issues in JavaScript. Touch events are a very sensitive feature and therefore a good knowledge about the calling stack of the default events is required. I will also refer […]
After a look into the history of Java build tools in the first part and a comparison of Gradle with Ant in the second part of this blog, we will now check if Gradle is a serious competition for Maven. Gradle is Like Maven, Just Better “All well”, you might say after reading the last part, “but I’m really […]
This article aims to give a clear representation of the relation between filenames and inodes, to explain what is an inode and which differences exist between a hard link and a symbolic link. 2.1 Filename as Hardlink to Inode On ext3 and ext4 (and some other filesystems) a file is stored internally as an inode […]
The first part of this Blog gave you a look into the history of Java build tools and the deficiencies of the two most common tools, Ant and Maven. This second and the third part will now show how Gradle works and why it sets a new level for Java build tools. Gradle is Like Ant, Just Better Like Ant, Gradle uses […]
With Apache Wicket there exists a component based Web Framework which supports the new WebSocket protocol.I want to give you a short introduction to Apache Wicket with the focus on the new WebSocket Support. It will be explained by developing a little real-time chat application in 7 steps. As I mentioned in my previous article WebSocket […]
If you are building a big client-side Javascript application, things like custom events for GUI updates and their listeners can cause big headache. Especially if you are not managing them on a central place. Javascripts only way to simulate custom events is a polling-like setTimeout() or setInterval() mechanism. I will not further explain why it […]
Introduction The ‘Command and Query Responsibility Segregation’ (CQRS) design pattern is based on the “Command-Query Separation” (CQS) principle from the book “Object-Oriented Software Construction“ by Bertrand Meyer (1988) and was first mentioned by Greg Young and Udi Dahan in 2010. This pattern has produced a lot of excitement and hype but the principle behind it […]