Ubuntu 14.04 - Fix Intel Centrino 6235 freeze & dramatically slow speed

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I've been using a combo Wifi/Bluetooth Intel Centrino 6235 mini-pci wireless adapter on my laptop with Ubuntu 12.04 for many months without problem.

But since I've upgraded to Ubuntu Trusty 14.04 LTS and I've started to use Bluetooth audio, my wifi speed has dramatically dropped.

Wireless performances have become so bad that system seems to freeze for few seconds, web surfing is sluggish and file transfer can go down to 20 kB/s !

This problem seems to come from some kernel evolutions where default parameters for iwlwifi module have changed and are not suiting Intel Centrino 6235 wireless adapters.

This article explains how to get back normal performance on a Intel Centrino 6235 mini-pci wireless adapter under Ubuntu 14.04 LTS.

It has been tested on a Ubuntu Gnome 14.04 LTS Amb64 installation but should be applicable to any other 14.04 flavor.

Read more: Ubuntu 14.04 - Fix Intel Centrino 6235 freeze & dramatically slow speed

Munin - SNMP plugin to display HP Color Laser printer Toner levels

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Munin allows simple supervision of any SNMP enabled device.

As HP Color Laser Printers are SNMP enabled, it becomes possible to follow all printer internal levels thru Munin.

This article provides a plugin implementation that allows you to follow all 4 toner levels (black, cyan, magenta & yellow) on any HP Color Laser printer.

With the help of this plugin you'll be able to display you printer toner level in almost real time. As a pre-requisite, you need a fuly operational instance of Munin supervision.

This has been tested on a HP Color LaserJet CM1312nfi MFP with Munin running on a Debian server.

Read more: Munin - SNMP plugin to display HP Color Laser printer Toner levels

Debian 7 - ZFS pools lost after ZFSonLinux update

dropcap-debian-zfsonlinux

In a previous article, I explained how to Setup ZFS with RAIDZ pool on your Linux Server .

Even if I'm doing regular updates to my Debian Wheezy server, I hardly reboot it, once every blue moon.

With these regular updates, my ZFSonLinux packages have been updated from version 0.6.2 to 0.6.3, from 0.6.3 to 0.6.4, from 0.6.4 to 0.6.4.1 , ... but without a reboot after every update.

To my surprise, after next reboot following a ZFSonLinux update, both my ZFS pools had disappeared. All my important server data where lost !

While searching the web for an explanation, I read lots of articles giving some tips and tricks, but nothing was really convincing. And more than that, lots of stuff was looking quite dangerous, with a high risk of definitely breaking the ZFS pools. After lots of searches, I finally found the real explanation to this huge problem on zfsforlinux discussion group.

Even if the solution is very simple, it is to my point of view worth writing this article. In fact, I hope it will help you to go straight to the solution. This should avoid you lots of frightening time ...

Please note that this solution is valid for servers where the / partition is not a ZFS one. Your ZFS pools should not host the root filesystem. They should be mounted during the boot process.

Read more: Debian 7 - ZFS pools lost after ZFSonLinux update

Ubuntu 14.04 LTS - Monitors Position Lost in Dual Display Setup

Ubuntu

If you are using a dual monitor display under Ubuntu Gnome Trusty 14.04 LTS, you may have noticed that both screen position can be set without any glitch thru the system parameters, but that this configuration is lost after every reboot.

In fact, if your screen positions are not the default proposed one (laptop screen at the left and second monitor at the right), it will be reset to the default one after every reboot. And, this occurs even if your monitor.xml configuration file is fully configured.

This article explains how to circumvent this Ubuntu misbehavior. It allows you to set your dual monitor positions and to make it survive after every reboot.

It has been tested under Ubuntu Gnome 14.04 LTS, but it should be applicable under other Ubuntu flavours.

Read more: Ubuntu 14.04 LTS - Monitors Position Lost in Dual Display Setup

Gnome Shell - Tips to help migration from Gnome 3.4 to Gnome 3.8+

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For the last two years, I've become a big fan of Gnome Shell. This desktop environment is becoming really robust and very well polished. Its simplicity is its strength.

But when upgrading from Gnome Shell 3.4 to 3.8+, you'll notice few differences in term of interface and behaviour. As a normal or power user you may be a little bit lost because of some evolutions. Some of the most noticeable differences are :

  • placement of Nautilus main menu
  • location of Nautilus scripts
  • location of Bookmarks file
  • behaviour of right menu to create new documents

This article focuses on some of these differences between Gnome Shell 3.4 and Gnome SHell 3.8 / 3.10. It gives some tips and clues to simplify your migration from version 3.4 to 3.8+.

It has been tested on a migration from Ubuntu 12.04 LTS to Ubuntu Gnome 13.10 & Ubuntu Gnome 14.04 LTS. But it should be applicable to any Linux distribution based on Gnome shell.

Read more: Gnome Shell - Tips to help migration from Gnome 3.4 to Gnome 3.8+

Ubuntu - Download TV replay and Videos from Firefox with YouTube-DL GUI

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Since TV replay sites have started coming out like mushrooms after a spring rain, it has always been a big challenge to be able to download their videos for offline viewing. The two major problems are that all the site are not using the same streaming protocol and that they change their site quite often. We also face this problem for YouTube video, as YouTube is slightly changing its site and protocol on regular basis.

Hopefully, youtube-dl project is there to help us. This project is very active and it can handle video stream downloading from most of the major video or TV replay sites. The project site provides an exhaustive list of supported sites (for example YouTube, DailyMotion and french Arte+7 & Pluzz are well supported).

The major drawback of this fantastic tool is also its strength : it is a command line tool. So it isn't very user friendly, as every time yo need to download a video, you have to open a terminal, cut & paste your browser URL, type the command line, wait for the download to finish and close the terminal.

It would be so confortable to be able to do a simple right click from any video or TV replay page, to select the video format you want to download and to follow the YouTube-DL download process in a progress dialog box.

This is exactly what this article helps you to achieve. It provides instructions to install all needed packages, to create a YouTube-DL GUI and to integrate it within Firefox. You'll then have the power and flexibility of youtube-dl fully integrated in Firefox browser.

Read more: Ubuntu - Download TV replay and Videos from Firefox with YouTube-DL GUI

Linux - Disable ByteMobile Web Pages Alteration

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If you are using connexion sharing on a 3G mobile network, you may have noticed that your web pages are sometime looking different when browsing from your home ADSL connexion or from your 3G mobile data connexion.

On 3G mobile network, some pictures may look ugly and some pages may even be completly broken. This happened to me when connected on Bouygues Telecom 3G mobile connexion to administrate some Joomla site. Administration was completly impossible, most of the pages giving unexpected errors or even remaining blank.

This comes from the fact that some ISP are using some stream compression technics to save some bandwidth on their mobile network. Not all ISP are doing so, but it is quite common nowadays, especially in the area where 3G networks are saturated.

The most widepread is developped by ByteMobile and it can aggregate all CSS code, recompress all images (making them look worse) and even inject some javascript code. In short, it may create a big mess out of your pages !

This article explains how to get rid of these alterations and get back the unaltered web pages you are expecting from any neutral internet service provider. It deals with a client side approach (as a user) and a web site approach (as a webmaster).

With this setup, pages served from your home or office connexion and from your mobile data connexion should remain exactly the same.

Read more: Linux - Disable ByteMobile Web Pages Alteration

Joomla - Minimize Display of Article's Authoring Details

JoomlaIf you run a Joomla site with a blog layout and you need to display authoring details (creation date, writer, ...) of your articles, you may have noticed these details are taking quite a huge display space.

By default they are displayed with this setup :

  • one line per item (creation date, update date, writer, ...)
  • Label Detail at the beginning of the first item
  • default date format very long (like Wednesday, 01 January 2014 10:00)

This article explains the simple steps needed to minimize article's authoring details to a single line on a typical Joomla site.

joomla-authoring-before

will become

joomla-authoring-result

This setup has been tested on a Joomla 2.5 installation.

Read more: Joomla - Minimize Display of Article's Authoring Details

Debian - Automate Monthly Connexion for Dyndns Free Accounts

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For so many years, http://www.dyndns.org/ has been providing free dynamic DNS accounts. For me, they have been the 'de facto' dynamic DNS provider. The proof : so many home routers, NAS, ... manufacturers are providing update clients for their DNS service.

But this wonderful time has come to an end. Dyn has simply removed any free offer from their catalog and thanks to their latest SLA, you are now supposed to connect to their web server at least once a month to keep your existing free dyndns account active. Even with an update client, your free account may be terminated if you do not connect periodically to their web site. This new policy is a deliberate free account killer.

If, like me, you've been relying for ages on their service for your personal web site, this new policy is a real pain in the neck. Who will think to connect once a month to a site to do ... nothing ? Hopefully (as usual in the computing world) there is a solution : instead of you in person, a small shell script can peridically to do the connection job for you. It will automatically connect to Dyn web site using your account.

So, this article explains how to create and setup a periodic script that will connect to Dyn login page. This connexion will be considered by Dyn as a user connexion. As a result, you'll be able to keep your free dyndns account active even without doing yourself the newly needed monthly connexion. This periodic script should allow you to save your free account from a killing SLA.

Read more: Debian - Automate Monthly Connexion for Dyndns Free Accounts

Debian - Self-hosted Web File Transfer with FileZ

Debian

debian-filez-logoFileZ is a Web file transfer project started by French university of Avignon.

It provides a simple and efficient way to upload and manage very big files that you want to share over internet. Everything is stored on your web server and handled through a web interface and some unique URLs.

University of Avignon has stopped to maintain the project, but it is still maintained by a small core team under Github repository https://github.com/FileZ/FileZ.

FileZ main features are :

  • handling of files up to 2 Gb
  • generation of short URL to retrieve these files
  • multiple users management with quotas
  • time limit and/or password management for files

Even if it is very simple to use, it is quite difficult to install. In fact, the project environment has evolved quite a lot but the provided installation procedure has not followed. As a result, whatever installation guide you find on the web is very much outdated.

So, this guide explains step by step procedure to fully install latest FileZ version 3.0 alpha from https://github.com/FileZ/FileZ on a Debian 7.0 server. It uses a MySQL database to manage users.

Read more: Debian - Self-hosted Web File Transfer with FileZ

Ubuntu - Paint Tool Sai Integration including Wacom Tablet Pen Pressure

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Paint Tool SAI has been running for a long time under linux with the help of Wine. But till date, Wacom tablet pressure is not handled properly. This problem is referenced as bug11846, opened in 2008 in WineHQ Bugzilla and still open.

Hopefully, the PlayOnLinux team has issued a patch for Wine version 1.5.5 that allows Paint Tool SAI to handle tablet pen pressure. But this patch doesn't seem to work with latest Wine versions.

So, this specific wine version has been added into PlayOnLinux database under 1.5.5-SAI name.

This guide explains all the steps to :

  • check if your Wacom tablet is recognised on your system
  • install PlayOnLinux and the patched Wine 1.5.5-SAI
  • install Paint Tool SAI
  • declare SAI files interaction for Gnome desktop

It has been tested with a Bamboo Fun CTH-661 tablet under Ubuntu Precise 12.04 Amd64 (Gnome 3.4) and Ubuntu Gnome 13.10 Amd64 (Gnome 3.8).

It should be applicable to many other Wacom tablet models and other Linux flavours.

Read more: Ubuntu - Paint Tool Sai Integration including Wacom Tablet Pen Pressure

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