If you’re using a Wacom intuos 3 graphics tablet with Gnome 3, then this little button layout illustration should be useful. Gnome’s built in Wacom configuration tool is great, but the numbers it assigns to the tablet buttons are not intuitive. Use this diagram to avoid a trial and error approach to function assignment.
So you’re using Fedora 19, you update yum one day, and a few days later you find some strange lockscreen behaviour. The look of your lockscreen has changed – a different background colour, clock size, and password box positioning. So far so good. But wait, why does a second lockscreen appear after you shoo away the first? Why can’t you type your password to the input field? Why can’t you get back to your desktop and unsaved work?
This bug affects people who have the Cinnamon desktop installed in a session using Gnome. Maybe you’ve installed Cinnamon desktop environment to try it out in the past, maybe other users on your machine are using it for their sessions, or maybe you’re using an app that relies on Cinnamon and has previously installed it as a dependency. My reason for having it is Nemo – the fork of Nautilus file manager, which is the default way to browser folders on Gnome 3, and which dropped a bucket load of functionality with a recent update, causing me and many others to move to the Cinnamon-oriented aquatically-named fork.
Cinnamon has it’s own lockscreen and this conflicts with Gnome 3′s own. Basically the “unlockable lockscreen” issue is caused by these two screensaver apps competing for your attention and your password, and between them they manage to prevent you from unlocking either one or both of them at all. Although this bug has apparently been fixed for Fedora 20, we Fedora 19 users are still suffering. Indeed yesterday I lost a whole page of notes to this bug, when I had to use ctrl+alt+backspace to force a session logout (you can enable this shortcut using Gnome Tweak Tools GUI; instructions reside in the Fedora Forums).
These instructions should save you when the bug has taken effect and you need to unlock your screen. A fix to stop the problem occurring in the first place is underneath.
Open a new virtual terminal using Ctrl+Alt+F2, login using your usual username and password, and execute:
Make sure it worked by ensuring that this command doesn’t find the process we just killed is still running:
sudo ps -e | grep cinnamon-screensaver
And now go back to your original X-based session using Ctrl+Alt+F1
Remove Cinnamon’s screensaver. Unfortunately this will remove the Cinnamon desktop entirely, including any Cinnamon-based apps you have installed, like Nemo. Well Nemo, so long and farewell. I look forward to your smarter file sorting and expanded file-handling extension set in Fedora 20. As root:
yum remove cinnamon-screensaver
Then log out and in again (Cinnamon’s screensaver should no longer auto start with the session).
Had an error like this while upgrading your system lately?:
insufficient disk space
need 40M free on /boot (0M free)
If so, it’s likely because you have lots of kernels installed and the automatic size of your /boot partition, as configured during Fedora’s installation wizard, has become insufficient. In my case I have real-time kernels installed from Standford University’s CCRMA repos, in addition to the standard Fedora kernels. Here’s how to free up some space.
- Find out which kernel you are currently using – you need to make sure you don’t try and remove that one by mistake:
- List all the kernels that you currently have installed:
yum list installed | grep kernel
- Now you can remove any kernels which you are no longer using. To do so you need to specify which version you want yum to remove. You can see the version of each kernel you have installed in the second column of the output of the above command. e.g.
3.10.7-100-fc18. To remove this kernel you would use the following command (adapt it according to the kernel version you want to remove):
yum remove kernel-3.10.7
Yum will tell you how much space will be freed and if any related kernel modules of the same version will be removed too (e.g. kmod-wl).
- That’s it, you should now have free space on /boot. Good luck!
Objective: achieve a reverse reverb effect using only MIDI and Free Software audio plugins. What we’re aiming for is the same piano effect that’s used on “Planisphere” by Justice (one of my favourite tracks).
Approach: I’ll use Qtractor Digital Audio Workstation (DAW), with a piano MIDI instrument, and the Impulse Response (IR) LV2 plugin. You could use any other DAW that supports LV2 plugins, e.g. Ardour.
- Make sure you’re using a GNU/Linux distribution that is configured to run with a real-time kernel, and has the JACK audio server set up and working.
- Open Qtractor, and create a new track, and set it up as your favourite MIDI piano instrument. In my case I used Calf Fluidsynth (available in many distribution repositories as part of the calf-plugins pack), loaded with a grand piano soundfont.
- Create a new clip and edit it with the “piano roll” (MIDI) editor to add some notes. Play the clip and make sure you can hear the sound. Here’s the clip that I used.
- Make sure you have the IR.LV2 plugin installed. This will handle the work of applying the reverse reverb effect. If it isn’t in your distribution’s software repositories, it can be easily compiled. Just download the source code, extract it, cd into its directory and run make, then make install. You’ll also need to install zita-convolver before compiling.
- In Qtractor, add IR as a secondary plugin to your piano instrument. IR should appear listed below the existing instrument plugin in the mixer window with a green light next to it showing that it’s enabled. If the IR plugin gui hasn’t appeared automatically, open it by double clicking on the IR plugin listed under the piano MIDI instrument in the mixer window.
- To make IR apply a reverb effect, we need an impulse response file to tell it what reverb pattern to use. I recommend the True M7 Impulse Pack, which contains a variety of high-quality WAV samples. Once downloaded and extracted, load a sample into IR by clicking “Open File” on the GUI. I’m using a room sample called “Blue Room L”. Here’s how my clip sounds with reverb applied.
- By this stage, a reverb effect should have been applied to your piano, and if you play it you should hear the difference. To get reverse reverb, we have to do some configuration however. Try setting the following:
Predelay = 0
Attack, Envelope, Length, Strech = 100%
Stereo In = 150%
Reverse = on (toggled)
Dry = Mute
Wet = -6dB
You can save this preset by clicking “Add” under “Bookmarks”. Choose somewhere sensible for the file and give it a name.By this stage you should see that the wave form in the graph preview window has changed, and that it illustrates a build up in volume representing the reverse reverb. Play your clip again – you should hear the desired effect!
- You’ve now achieved the desired sound effect, but one problem remains – there’s now an audio delay between then the MIDI note should be played according to the tract, and when you hear the sound through speakers. This will obviously cause havok with the timing of your track and the other instruments that don’t have any delay in playback. There may be a more elegant solution to this problem, but here’s a workaround that works for me. Simply shift your piano clip(s) two beats (half a bar) earlier (to the left). With the IR settings above, this should correctly compensate for the delay. Now if you add other tracks, they should sound syncronised with your reverse reverbed track.
- That’s it, good luck!
SoundFont is a technology for generating sample-based instrument sounds. It’s supported on GNU/Linux by a variety of apps, including Qsynth, which can be used as an external JACK instrument and connected to Digital Audio Workstations like Ardour 3 and Qtractor.
Many SoundFont instruments are freely available, but some of them are compressed and instead of of the .sf2 file extension, are .sfArk files. sfArk is a custom compression system, but fortunately these too can be used on GNU / Linux. Here’s how.
- Install the dependencies (this command is for Debian / Ubuntu based systems):
sudo apt-get install git zlibc
- Clone the sfArkLib repository:
git clone https://github.com/raboof/sfArkLib.github
- Compile and install sfArkLib by following the github instructions
- Clone the repository of the sfArkXTm command line utility:
git clone https://github.com/raboof/sfArkXTm
- Compile sfArkXTm:
Note: the sfArk command line utility for extracting sfArk files is only installed in directory that you compiled it in. Unless you move the binary to a system directory, or create a synlink to it, you will always have to specify the path to the binary when you use the utility.
- Convert your .sfArk file to a standard .sf2 file:
~/sfArkXTm/sfArkXTm yourSfarkFilename.sfArk yourSfarkFilename.sf2
That’s it. Good luck!
Today Hemlis, a proposal for a new encrypted mobile messaging app, received $125,000 in crowdfunding. It’s wonderful to see ambitious new software projects get support from the community, especially when they are Free Software which can be used, studied, shared, and improved by everyone. But is this really the case with Hemlis?
A few moment’s thought are all that’s required to realise that the only trustworthy app is a Free Software app. This is why the US Government goes to the trouble of certifying Free Software encryption cyphers as their national standard, why the NSA uses GNU/Linux and Hadoop to monitor the world, and why everyone from the armed forces to drug smugglers turn to Free Software network tools like Tor to cover their tracks online. After all, what use is security that cannot be verified, because its workings are secret?
Considering the obviousness of these facts, Hemlis, self-billed as “The Beautiful & Secure Messenger”, could reasonably be expected to be 100% Free Software. Many indicators point to this not being the case however.
The crowd-funding model Hemlis used rewards donors with “unlock codes” which extend app functionality with picture messaging, among other things. This business model is as old as the hills, and just like the shareware and neo-proprietary (aka ‘open core’) apps that came before it, provides exclusivity to paying customers by artificially locking other users out. The code that locks other users out we refer to as an “anti-feature” because its functionality that’s built for the sole-purpose of inhibiting what a user can do. For an excellent (and terrifying) explanation of how anti-features are harming humanity and their environment hear Benjamin Mako-Hill’s recent keynote speech on the subject.
But shareware / neo-proprietary software cannot, by definition, be Free Software. One of ways Free Software protects users is by making them immune to anti-features, because when you have the source code to a program, you can simply remove or disable unhelpful code to suit your needs. Because anti-features serve nobody but the original developer, they don’t last long in the wild, and usually get swiftly removed. The Hemlis founders are smart people, and among them is Peter Sunde, famous for his leading role in the Pirate Bay, also known as “the World’s most resilient BitTorrent tracker”. Peter et al wouldn’t base their funding model on a reward system that was destined to be undermined on release day, so some part of the initial Hemlis app must be non-Free Software, or perhaps all of it. And as we know, non-Free Software cannot be trustworthy software, which is Hemlis’ stated purpose.
But it’s not just the Hemlis mobile apps that are looking suspiciously closed. From the official FAQ:
We have all intentions of opening up the source as much as possible for scrutiny and help! What we really want people to understand however, is that Open Source in itself does not guarantee any privacy or safety.
As the quote says, the availability of source code is not a sufficient condition for security or privacy. Availability of source code is, however, a necessary condition for those things. It doesn’t sound like the team are committed to Free Software, privacy, or security from the above statement – if they were, then they wouldn’t imply that 100% source code availability is impossible, which, as they are writing the app themselves, is patently not the case. The FAQ continues:
It sure helps with transparency, but technology by itself is not enough. The fundamental benefits of Heml.is will be the app together with our infrastructure, which is what really makes the system interesting and secure.
Their explanation emphasises the critical relationship between the Hemlis mobile client and the developer’s own server infrastructure. That sounds like a centralised service, i.e. a single messaging server to which all the mobile clients connect, which is the same network model that so many other proprietary messaging apps use, including BlackBerry Messenger and What’s App. However their description hints at Hemlis’ own control of the server as well as centralisation. But why should the Hemlis dev team be the only ones to run a Hemlis messaging server? It remains to be seen whether the quote is referring to infrastructure software, or infrastructure service – e.g. whether the dev team will make the Hemlis messaging server Free Software, or just keep it for themselves along with control over the network and knowledge of where all our messages go.
These observations raise important questions about how trustworthy Hemlis will be when it’s finally available, and whether $125,000 of community good will shall be invested in Free tech for the good of everyone, or (at least) partly closed tech for the good of the Hemlis project founders. I’ve already sought answers to my questions on Twitter but so far received no response. Hopefully we’ll all have more information soon.
And until Hemlis materialises in an app store near you, you can use an existing Free Software messaging app that has already had its privacy tested and it’s decentralised network independently deployed: Kontalk is in both the F-Droid and Google Play stores, ready for your use. I’ve been using it for cost-free text and picture messaging back to the UK from Germany since I moved four months ago. If you’re looking for a glitzy website featuring a heartfelt plea for your money from a celebrity, you’ll be disappointed. But if you’re looking for bullet-proof privacy and seamless integration with Android, try Kontalk.
I’m trying out Murmur / Mumble-server at the moment for conference calls and meetings for FSFE campaigns. The service is great, and audio quality top-notch. Installation and configuration was generally very simple.
In order to have private conversations however (where uninvited users cannot participate), you must first log in as the pre-configured admin user, called ‘SuperUser’. Achieving that was rather confusing on Debian, so for future reference, here’s how to do it.
- Set the SuperUser password via the Murmur server CLI:
sudo /usr/sbin/murmurd -ini /etc/mumble-server.ini -supw <password>
You must run the command as root, and you must specify the .ini file. Do not use
murmur-user-wrapper, which Debian provides.
- Connect to the Murmur server using the Mumble desktop client, specifying username SuperUser, and the password that you set above.
Ardour 3 is the most powerful Free Software music software currently available. Although Fedora isn’t a GNU/Linux distribution that’s designed for audio professionals, with a little work it can be configured to process sound with low-latency (without 20+ millisecond delays or artefacts like pops and crackles), and get easy access to repositories with many recent pro-audio apps.
We’ll compile Ardour from its source code in this tutorial, because this will get us the very latest version (with features and bug fixes missing from older copies), and because Ardour recently switched to a payment-oriented package distribution model which promotes source compilation as the installation method for people who aren’t Ardour donors.
We’ll also set up the CCRMA package repositories, which contain many audio apps not found in the default Fedora repos, and most importantly will supply us with a real time kernel (which Ardour, and low-latency operation in general, requires). The CCRMA repos are provided by the Stanford Center for Computer Research in Music and Acoustics.
These instructions are designed to work with Fedora 18 and Ardour 3.1.1, though I expect they will work as well with later versions of both. If not, let me know and I’ll try and tweak the guide.
- Install package dependencies required by Ardour:
yum install git jack-audio-connection-kit-devel libsndfile-devel liblo-devel aubio-devel cppunit-devel cwiid-devel liblrdf-devel libsamplerate-devel lv2-devel serd-devel sord-devel sratom-devel lilv-devel flac-devel gtkmm-2.4-devel gtkmm24-devel libgnomecanvas-devel libgnomecanvasmm26-devel suil-devel libcurl libcurl-devel uuid uuid-devel libuuid libuuid-devel lib fftw3 fftw3-devel liboggz liboggz-devel
- Setup the CCRMA repositories (more detailed info in the Fedora manual):
su -c 'rpm -Uvh http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/\
- Update existing packages and refresh what’s available:
- Install real-time (low-latency) kernel and drivers from CCRMA:
yum install planetccrma-core
- Reboot your machine to use your new real-time kernel.
- Download Ardour via Git and compile it by following the simple official instructions (see “Building Ardour 3.x”). I recommend not installing Ardour unless you really need to (installing is the final step in the official instructions that simply creates links within Fedora’s menus etc. and isn’t required for compiling / running / using Ardour).
- Start the jack sound server by running qjackctl (either from system menu or CLI), and click on “start”.
- Run your newly compiled Ardour (execute this from within the directory you compiled Ardour in):
Those are all the necessary steps and you should now have a fully functional copy of Ardour! I recommend installing some additional LV2 plugins however to extend the built-in MIDI instruments that are available within Ardour.
- (Optional) Install additional synthesisers for Ardour:
sudo yum install lv2-triceratops lv2-synthv1 lv2-calf-plugins lv2-calf-plugins lv2-mdaEPiano
Those synths should appear automatically as available MIDI instruments when you restart Ardour.
I hope that running Ardour in the way I’ve described will whet your appetite to dive more deeply into audio production on GNU/Linux. If so, I recommend using a dedicated GNU/Linux distribution for audio work, because it’ll provide you with many more tools and features, and save you having to manually configure them all yourself. For now KXStudio is my clear favourite.
Good luck, and let me know how you get on in the comments
Twidere is a great Free Software Twitter client for Android that also works with identi.ca. The identi.ca server must be configured manually however in order to do this. The below instructions work with Twidere 0.2.1.
- Tap the accounts tab (fourth icon from left with multiple human silhouettes)
- Tap the ‘+’ button top right to add a new account
- Tap the server icon top right next to the spanner icon to configure the server
- Change the REST Base URL to https://identi.ca/api
- Set the Auth Type to ‘Basic’
- Tap OK
- Enter your identi.ca username and password
- Tap ‘Sign in’
That’s it! Good luck.
Robin Appelman has recently rewritten ownCloud’s filecache components, and made a variety of improvements to the filesystem handling classes. Some of the changes break compatibility with existing apps however, especially if they use the filecache directly.
I have just finished making the encryption app compatible, and here are the instructions I followed (originally posted by Robin to email@example.com):
OC_FilesystemViewhave been renamed to
\OC\Files\View. For backwards compatibility they are still available under their old name for now but that will probably change in the future.
The filesystem cache is accessible with the following functions:
\OC\Files\Filesystem::searchByMime($mimetype)(accepts both ‘text/plain’ and wildcard ‘text’ style mimetypes)
If you need to access the cache for files outside the user’s home directory, the same functions are available in \OC\Files\View.