How to Know if a File on Linux is Sparse?

A sparse file is a file which does not take more space on disk than needed. Such a file is usually used to store a partition image on disk, for instance with a virtualization solution like Xen.

Copy Sparse Files with Rsync

Updating my backup script that is using rsync, I have just realized that without further options, rsync does not handle well copying sparse files (i.e. files that are for instance holding a file system and that just take the space needed by their actual size). A consequence is…

Sparse Files — Commands Overview

I was just checking which commands are supporting sparse files. I post hereafter a short overview of what I found out (working on Linux).

• Create a sparse file of 20 GiB: 
   dd if=/dev/zero of=foo bs=1 count=1 seek=20G

Using Passbook for Boarding a Flight

On my trip to Berlin for the Scala Days conference, I used Passbook for the first time to store my boarding pass. I thought it would be interesting to share this first paperless boarding experience with you.

Java Quiz of the Day II

What gives:

Integer a = 100, b = 100;
Integer c = 200, d = 200;
System.out.println( (a == b) == (c == d) ); // A

Response: counter intuitively, the program prints ‘false’ out. Integer in Java is a non-native class, where ‘==’ means…

WYSIWYG HTML Editor in Javascript

Quite interesting. I saw on Philip Wadler’s blog a link to the Tiny MCE WYSIWYG HTML editor implemented in Javascript, that is completely web-based. Don’t hesitate to follow the link for a quick example of the capabilities.

Ultimate Configuration Guide for Linksys SPA, PAP2 & Sipura

Definitely worth a look. The page shows an example configuration for a Linksys SPA, PAP2 or Sipura VOIP device for different VOIP operators. Unfortunately the explanations are in German. Otherwise, lots of details, relevant…

Java Quiz of the Day

Java quiz of the day (easy): what gives

Object[] a = new Integer[]{};
List<Object> b = new ArrayList<Integer>();

Response: we get an exception on the second line:

Type mismatch: cannot convert from…

AJAX Domain Name Availability Check

This small AJAX Whois availability check page, seen on Roberto’s blog, is very handy:

AJAX Domain Name Availability Check

Better Keyboard Shortcuts for Mac X11 Apps

I have always found the integration of X11 apps in Mac OS X quite alright, apart from the fact that for a native Mac application you use the apple key for keyboard shortcut and for an X11 app you use the control key. So, for instance, if you want to copy…