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Migrating from owncloud 9.1 to nextcloud 11

2017-02-10 23:33 UTC  by  madman2k

First one should ask though: why? My main motivation was that many of the apps I use were easily available in the nextcloud store, while with owncloud I had to manually pull them from github.
Additionally some of the app authors migrated to nextcloud and did not provide further updates for owncloud.

Another reason is this:

the graphs above show the number of commits for owncloud and nextcloud. Owncloud has taken a very noticeable hit here after the fork – even though they deny it.

From the user perspective the lack of contribution is visible for instance in the admin interface where with nextcloud you get a nice log browser and system stats while with owncloud you do not. Furthermore the nextcloud android app handles Auto-Upload much better and generally seems more polished – I think one can expect nextcloud to advance faster in general.


For migrating you can follow the excellent instructions of Jos Poortvliet.

In my case owncloud 9.1 was installed on Ubuntu in /var/www/owncloud and I put nextcloud 11 to /var/www/nextcloud. Then the following steps had to be applied:

  1. put owncloud in maintenance mode
    sudo -u www-data php occ maintenance:mode --on
  2. copy over the config.php
    cp /var/www/owncloud/config/config.php /var/www/nextcloud/config/
  3. adapt the path in config.php
    # from 
    'path' => '/var/www/owncloud/apps',
    # to
    'path' => '/var/www/nextcloud/apps',
  4. adapt the path in crontab
    sudo crontab -u www-data -e
  5. adapt the paths in the apache config
  6. run the upgrade script which takes care of the actual migration. Then disable the maintanance mode.
    sudo -u www-data php occ upgrade
    sudo -u www-data php occ maintenance:mode --off

and thats it.

Categories: News

OGRECave 1.10 release

2016-12-22 01:26 UTC  by  madman2k

The 1.10.0 release of the OGRECave fork was just created. This means that the code is considered stable enough for general usage and the current interfaces will be supported in subsequent patch releases (i.e. 1.10.1, 1.10.2 …).

SampleBrowser running GLES2 on desktop

This release represents more than 3 years of work from various contributors when compared to the previous 1.9 release. At the time of writing it contains all commits from the bitbucket version as well as many fork specific features and fixes.

If you are reading about the fork for the first time and wonder why it was created, see this blog post. For a comparison between the github and bitbucket version see this log.

For a general overview of the 1.10 features when compared to 1.9, see the OGRECave 1.10 release notes.

The highlights probably are:

  • upstream Python bindings as an component
  • improved GL3+/ GLES2 renderers
  • A new HLMS Component implementing physically based shading
  • SDL2 based input handling
  • Bites Component for rapid prototyping of applications
  • Emscripten platform support

For further information see the github page of the fork.

Categories: Graphics

On OGRE versions

2016-08-05 12:24 UTC  by  madman2k

Currently one can choose between the following OGRE versions
1.9, 1.10, 2.0 and 2.1

Click to read 1288 more words
Categories: Graphics

Creating PyGTK app snaps with snapcraft

2016-07-09 13:45 UTC  by  madman2k

Snap is a new packaging format introduced by Ubuntu as an successor to dpkg aka debian package. It offers sandboxing and transactional updates and thus is a competitor to the flatpak format and resembles docker images.

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Categories: Articles

Introducing the OGRE fork on GitHub

2016-05-02 14:38 UTC  by  madman2k

in this post I want to introduce the OGRE fork on github. The goal of the fork is to provide a stable and reliable OGRE 1.x series while at the same time modernizing parts under the hood updates.

Click to read 1522 more words
Categories: Graphics

Learning Modern 3D Graphics Programming

2015-12-29 22:26 UTC  by  madman2k

one of the best resources to learn modern OpenGL and the one which helped me quite a lot is the Book at – or lets better say was. Unfortunately the domain expired so the content is no longer reachable.

Luckily the Book was designed as an open source project and the code to generate the website is still available at Bitbucket. Unfortunately this repository does not seem to be actively maintained any more.

Therefore I set out to make the Book to be available again using Github Pages. You can find the results here:

However I did not simply mirror the pages, but also improved it at several places. So what has changed so far?

  • converted mathematical expressions from SVG to inline MathML. This does not only improve readability in browsers, but also fixes broken math symbols when generating the PDF.
  • replace XSLTHL by highlight.js for better syntax highlighting
  • added fork me on github badge to website to visualize that one can easily contribute
  • enabled the Optimization Appendix. While it is not complete, it already provides some useful tips and maybe encourages contributions.
  • updated the Documentation build to work on Linux
  • added instructions how to Build the website/ PDF Docs

hopefully these changes will generate some momentum so this great Book gets extended again. As there were also non-cosmetical changes like the new Chapter I also tagged a 0.3.9 release.

I the process of the above work I found out that there is also a mirror of the original Book at This one is however at the state of the 0.3.8 release, meaning it does not only misses the above changes but also some adjustment happened post 0.3.8 at bitbucket.

Categories: Graphics

UEFI is the successor to BIOS for communicating with the Firmware on your Mainboard.
While the first BIOS was released with the IBM-PC in 1981, the first UEFI version (EFI 2.0) was released 25 years later in 2006 building upon the lessons learned in that timespan. So UEFI is without any doubt the more modern solution.

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Categories: Articles

Updating Crucial MX100 Firmware with Ubuntu

2015-04-10 20:14 UTC  by  madman2k

There has been a Firmware update for the Crucial MX100 to MU02. In case you are running Ubuntu there is an easy way to perform the update without using a CD or USB Stick.

As the firmware comes in form of an iso image containing Tiny Core Linux, we can instruct grub2 to directly boot from it. Here is how:

  1. append the following to /etc/grub.d/40_custom:
    menuentry "MX100 FW Update" {
     set isofile="/home/<USERNAME>/Downloads/MX100_MU02_BOOTABLE_ALL_CAP.iso"
     # assuming your home is on /dev/sda3 ATTENTION: change this so it matches your setup
     loopback loop (hd0,msdos3)$isofile
     linux (loop)/boot/vmlinuz libata.allow_tpm=1 quiet base loglevel=3 waitusb=10 superuser rssd-fw-update rssd-fwdir=/opt/firmware rssd-model=MX100
     initrd (loop)/boot/core.gz

    read this for details of the file format.

  2. run sudo update-grub
  3. reboot and select “MX100 FW Update”
  4. Now you can delete the menuentry created in step1

Note that this actually much “cleaner” than using windows where you have to download 150MB of the Crucial Store Executive Software which actually is a local webserver written in Java (urgh!). But all it can do is display some SMART monitoring information and automatically perform the above steps on windows.

Header Image CC-by MiNe

Categories: Articles

If you want to get your Xbox One/ Xbox 360 running on ubuntu you basically have the choice between the in-kernel xpad driver and the userspace xboxdrv driver.

Most of the guides recommend using xboxdrv as xpad has been stagnating. However using xboxdrv has some disadvantages; as it runs as a daemon in userspace you have to manually take care of starting/ stopping it and giving your user access to the virtual devices it creates.
Xpad on the other hand just works as any other linux driver directly inside the kernel which is more  efficient and hassle free.

Fortunately while pushing SteamOS Valve has updated the xpad driver bringing it on par with xboxdrv:

  • they added support for Xbox One Controller
  • they fixed the communication protocol – no more blinking controller light

Update July 22, 2015

Unfortunately there are still several issues with the SteamOS driver. This follow-up post discusses them and the solutions in detail.

The bottom line is that I updated the official linux driver with chunks found in the SteamOS driver, as well as in several patches floating around the internet. Code and install instructions are available at Github.

Categories: News

The build-in opencv line drawing function allows to draw a variety of lines. Unfortunately it does not allow drawing a gradient line interpolating the colors at its start and end.

However implementing this on our own is quite easy:

using namespace cv;

void line2(Mat& img, const Point& start, const Point& end, 
                     const Scalar& c1,   const Scalar& c2) {
    LineIterator iter(img, start, end, LINE_8);

    for (int i = 0; i < iter.count; i++, iter++) {
       double alpha = double(i) / iter.count;
       // note: using<T>(iter.pos()) is faster, but 
       // then you have to deal with mat type and channel number yourself
       img(Rect(iter.pos(), Size(1, 1))) = c1 * (1.0 - alpha) + c2 * alpha;
Categories: Graphics

How to manually update a deb package from source

2014-03-15 12:03 UTC  by  madman2k

Probably everyone has encountered a package in Ubuntu which was not the newest released version while one for some reason needed the newest one. The first step is to search for a PPA with the desired version. But what if there is no such PPA or you want to build the version yourself? This is where this guide comes in. Note however that this is not aimed at ordinary users – you need some experience with programming/ compiling to successfully build a package.

Before you start

Before you start make sure that you have source packages enabled in your software sources.
Next you obviously need the upstream source tar-ball of the new program which should look something like <packagename><version>.tar.gz.
Download this tar-ball to a new directory <somedir> and extract it there.

Updating Package info

For the following commands I assume you are in the previously created directory <somedir>.

First we need to get the old version of the source package

apt-get source <packagename>

This will download and extract the old source package into <packagename><oldversion>.

Now we need some helper scripts to perform the upgrading as well as the build-time dependencies of the package

sudo apt-get install dpkg-dev devscripts fakeroot
sudo apt-get build-dep <packagename>

Next change into the extracted sources of the old package and update the packaging

cd <packagename>-<oldversion>
uupdate -v <newversion> ../<packagename>-<newversion>.tar.gz

# change into the extracted new package
cd ../<packagename>-<newversion>

# update version info
dch -l ~ppa -D $(lsb_release -sc)

For more information see the Debian New Maintainers Guide.

Building the program

To trigger a rebuild of the program simply execute

Uploading your version to a PPA

To upload a package to a PPA you first need to sign it to prove that you are the author. To do this you have to execute the following in the <packagename><newversion> directory

debuild -S

Furthermore you need the upload tool dput to actually perform the uploading

sudo apt-get install dput

Now change to <somedir> and execute

dput ppa:<your_username>/<repository> <source.changes>

You can find more information at Launchpad.

Categories: News

Secure Owncloud setup

2014-02-22 10:53 UTC  by  madman2k

While the Owncloud Manual suggests enabling SSL, it unfortunately does not go into detail how to get a secure setup. The core problem is that the default SSL settings of Apache are not sane as in they do not enforce strong encryption. Furthermore the used default certificate will not match your server name and produce errors in the browser.

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Categories: Articles