Adding a badge to the unified toolbar on Mac OS X

Mac OS X and the applications running on it are known for being sometimes unusual in the look and feel. For some reason developer on Mac OS X seems to be more creative than on other platforms. For an application developer which deals with user input it is important to make any user interaction as useful as possible and present this information in a way which is on the one side as much less annoying as possible but also attractive and informative on the other side. Lastly I was thinking about how to show the users they are using a beta version, which should remind them that this is not production ready software, but on the same time make it easy to respond to bugs they find in this pre-release. The solution, I came up with, was a badge in the toolbar which shows this is a release which is definitely in a testing phase, but also allows the user to double-click to give a respond to this particular version. In the following post I will show how to do this.

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Creating file shortcuts on three different operation systems

As you may know, developing for multiple platforms is one of my strengths. Strictly speaking, it’s a basic requirement if you are involved in such a product like VirtualBox, which runs on every major (and several minor) platform available today. Beside the GUI, which uses Qt and therewith is portable without any additional cost (which isn’t fully true if you want real native look and feel on every platform, especially on Mac OS X), all the rest of VirtualBox is written in a portable way. This is done by using only C/C++ and Assembler when necessary. Everything which needs a different approach, because of the design of the OS (and the API’s which are available there), is implemented in a platform dependent way. In the history of VirtualBox, several modules are created and grown by the time, which makes it really easy to deal with this differences. For stuff like file handling, paths, strings, semaphores or any other basic functionality, you can just use the modules which are available. On the other side it might be necessary, for a new feature we implement, to write it from the ground. In the following post I will show how to create a file shortcut for the three major operation systems available today.

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Understanding some of the mysteries of launchd

Have you ever wondered how Mac OS X knows which file type belongs to which application? On Windows there is the registry. An installer writes the necessary info into it. Most applications on Mac OS X doesn’t come with an installer, they are just moved from the downloaded DMG file to the /Applications folder. So a developer doesn’t have the ability to take action when the user “install” the application. Anyway there is no need to provide an installer for just this task, cause Mac OS X register file type associations on the first start of the application. In the following post, I will show how to do this, but furthermore I will show where this information is stored and how it could be reseted.

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Getting the backtrace from a kernel panic

You may know the following situation. You arrive in the morning in the office, do what you always do and check out the latest changes of the software you are working on. After a little bit of compile time and the first coffee you start the just build application. Bumm, kernel panic. After rebooting and locking through the changes you may have an idea what the reason for this could be. A colleague of you is working on a fancy new feature which needed changes to a kernel module. As you almost know nothing about this code you seek for help and, as it of course not happen on his computer, he is asking for a backtrace of this panic. You have two problems now. First you need to see the panic yourself and second it would be nice to get a copy of the backtrace for sharing this info within a bugtracker. In the following post I will show how both aims could be easily archived.

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Using suppression files with Valgrind

Valgrind is one of the great tools in the long list of freely available applications for development. Beside several profiling tools it also contains a memory checker. Leaking memory is one of the more common errors a programmer could step into. Basically it means to forget freeing memory (or in a more general sense: any resource) a program has acquired. If you are a perfect developer, this will never happen to you. If you are a good developer it may happen and that’s where Valgrind will save you some trouble. As most of the developers out there are more or less good developers, their programs produce memory leaks, too ;). The right solution for this, is of course to write a bug report. But there are times where this isn’t possible or you are in hurry and don’t want to see all the errors of a third-party library you link against.

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Changing the default behavior of built-in Cocoa controls

Apple has many task specific controls built into Cocoa. They are all well designed and have most of the functionality a user and a developer expect. One of this controls is the NSSearchField. This control has a special design which allows the user to recognize the provided functionality with ease. It is so well-known that Apple uses the design even on there website. It has support for menus (e.g. for recent search items), auto completion, a cancel button, and so one. Although this is mostly feature complete, there are sometimes cases where you like to extend it. In this post, I will show how to add another visual hint to this control when a search term isn’t found. The aim is to change the background of the underlying text edit to become light red to visual mark the failed search.

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Installing Linux on a USB hard disk for the MacBook Pro

One of the features of Mac OS X I love, is the possibility to install Mac OS X on any attached removable media, like a FireWire or USB hard disk. This makes it really easy for me to test VirtualBox on the several versions of Mac OS X we support (formerly Tiger, now Leopard and Snow Leopard). The advantage of this setup is that I don’t waste disk space for operation systems I usually don’t use very often. Currently I have a 150GB hard disk in my MacBook Pro which is really not that much if you deal in the virtualization business. There are several test VM’s of any kind of guest operation systems and of course the ISO’s to install them. The second main OS, I do much of my work, is Linux. For this I have a standard PC with Gentoo on it, which have all that I need. Unfortunately this doesn’t really help when I on travel. As I soon be away for some time, I decided I need, at least for testing, the same flexibility mentioned above for a Linux installation. And here the problems start to arise. Of course Apple didn’t really support installing other OS’s than Mac OS X on Apple hardware. Yes, there is Boot Camp, but this is mainly for Windows, is very inflexible and doesn’t really help if you try to install something on another place than the integrated hard disk. There are projects like rEFIt, which even makes Boot Camp superfluous, but this project has really bad USB boot support. In the following I will explain how it is even possible to install Ubuntu 9.10 on a USB hard disk.

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Why an ending slash on a URL matters (or not)

Recently I read a report from Google about the status of their own Web sites in terms of Search Engine Optimization (SEO). Uhh, Google, the search engine giant, is looking how the own sites are behaving when a Web crawler is stumble over them! To be honest, it’s fully clear to me that in such a big company, like Google, not all is perfect in the sense of cooperative appearance. There are different projects, different teams, with different strengths and weaknesses, different priorities and of course different managers. To summaries the report: In some areas Google does a good job, but in most it doesn’t.

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FRITZ!Box tuning part 3: Using the VoIP phone line from everywhere

The contract with my Internet service provider includes a VoIP connection. Together with the FRITZ!Box 7270 all phone calls are done over the Internet, an additional conventional phone connection isn’t necessary anymore. One of the benefits of this is that you can connect to your registrar from everywhere in the world. But that’s theory, cause e.g. my provider doesn’t allow a connection if you are not in the network of the provider itself. Of course there are free services like sipgate or even Skype. There you could make free calls within the services itself, but as soon as you like to call a real phone number you have to pay. They are cheap, no question, but my contract includes a flat rate within Germany. That’s even cheaper. So what I like to do is to use my VoIP phone connection even when I’m not at home. In the following third part of the FRITZ!Box tuning series, I will explain how to achieve this. As already said in the first two post, where you at least should read the first one, I’m not responsible for anything happens to your FRITZ!Box after you have tried what is described here.

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FRITZ!Box tuning part 2: Access your home network with OpenVPN

AVM has built a VPN server into the FRITZ!Box, why should I use some other software for this job, you may ask. The reason is quite simple: the build in one is a piece of closed source software written by AVM and there is only one official client which could be used to connect to it, the FRITZ!VPN software. This client software is only available for the Windows operation system family and so by no means anything useful to me. I’m pretty sure they are using some official protocol like IPSec, so it might be possible to connect to the FRITZ!Box with other clients as well, but that’s something I didn’t want to try. OpenVPN on the other side is a rock solid open source software which could be used from many popular OS’s these days. Even graphical clients, like TunnelBlick for Mac OS X, are available. So here comes the second article of the FRITZ!Box tuning series, which will explain how to convert your FRITZ!Box into a OpenVPN server, where any number of clients can concurrently be connected. I highly recommend to read the first part of this series, because this post is build on top of the stuff done there. This count especially for the filesystem layout on the usbstick and the way additional software is started. Also in the following it will be helpful to have ssh access to the FRITZ!Box all the time. As already written in the first part, there is no guarantee that the information presented here will work on your side or that I’m responsible for anything happen to your FRITZ!Box. In preparation of the following you need access to a second OpenVPN installation which will be used to create all necessary certificates and keys and which could be used to test the installation afterward. I’m using a Gentoo Linux host where you could install OpenVPN simply by executing emerge openvpn. Make sure you have the examples USE flag set to get all the helper scripts which make the life much more easier.

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