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…

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.

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

NFS Automount with Snow Leopard

Before upgrading to Snow Leopard, I was using the NFS automount capability of Mac OS X. It was a handy way for my laptop to connect to my home NAS server (a linux box running Ubuntu).

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…

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…

Time Machine: Handy but Bitchy!

I have been spending the last couple of days of my spare time performing a simple operation with my mac, yet slightly more complicated than expected: merge the two partitions of my hard drive into one. This was necessary since I did a mapping, quite usual on Linux, where my…

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…

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.

Tomato on WRT54GL: LED shows WIFI status

Something I wanted to do since ages. My wireless router WRT54GL running the Tomato firmware has a button on the front, which can be used to toggle WIFI on and off. The router has also a rather visible LED indicator, behind the button, that is unfortunately…