Category Archives: Linux Tips

How to install Ubuntu 12.04 on old computers with non PAE CPU

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When I tried to install Ubuntu 12.04 on an old ThinkPad X40 I was surprised to discover this warning on my screen:

This kernel requires the following features not present on the CPU:
pae. Unable to boot - please use a kernel appropriate for your CPU.

In few words I wasn’t able to install Ubuntu 12.04 because the kernel on Ubuntu 12.04 was not supporting my CPU and I was really upset because I have always promoted Linux distributions as the most versatile and appropriate OS to keep using “old” hardware.

Sincerely, as described in an older post, I previously decided to install MATE desktop environment because the graphic cards on many laptops didn’t support Unity and Gnome 3 but this was the first time I had to renounce the installation of Ubuntu. I didn’t want to surrender to this difficulty (that appeared to me as a bug)!

First of all, I discovered that pae is “a feature to allow 32-bit x86 processors to access a physical address space (including random access memory and memory mapped devices) larger than 4 gigabytes“. After I clarified this point, I was not sure that my processor was totally inadequate to support Ubuntu 12.04.

After some web surfing I discovery that there are two easy solutions to avoid this problem.

1 – As first solution you can install Lubuntu (my choice) or Xubuntu on your computer then you can install the ubuntu-desktop using the Package Manager.

2 – If you prefer not to use the Package Manager you can install Ubuntu 11.04 or 11.10 and then upgrade Ubuntu to 12.04.

More in general, it is also possible to assume that if you have a non PAE CPU, your hardware could not be able to support the Unity desktop. For  this reason you can keep your Lubuntu – Xubuntu (based on the light but effective LXDE desktop) or switch your desktop environment to Gnome (the Classic, of course) installing the gnome package instead of ubuntu-desktop.

In any case, if you want to know if your CPU supports pae you have to open a Terminal and type:

grep --color=always -i PAE /proc/cpuinfo

If something like “flags: fpu vme de pse tsc msr pae mce cx8…” outputs on your Terminal, you have a pae CPU otherwise your CPU doesn’t support pae.  AddThis

The good third choice: MATE desktop environment. The traditional but rock solid solution for the Unity unhappy users (when also Gnome fails)…

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My first Linux OS was a Knoppix but I had so many problems with the hardware drivers, the LAN configuration and the monitor settings that I was really discouraged. After many tests I decided that Ubuntu was the right OS for my notebooks and I continued to use it without any particularly matters till Unity.

Unity is nice to see, intuitive but if you use your OS in a stressful way (I mean doing three or four different tasks all together: reading emails, talking with Skype and writing on LibreOffice), you spend too much time looking for the icon you need to launch the right program. The vertical monitor space has not enough room to visually show all the icons related to programs I use everyday. Surely this is my personal matter but I actually prefer the “old” graphic interface. For this reason I decided to install Gnome 3 but my vetust IBM Thinkpad crashed a couple of time in a week.

To my surprise also the Gnome Classic option encountered some crashes due to the amount and diversity of the software I installed on my laptop during the last years.

As usual, after some web searches I found a solution: MATE. This particular desktop environment is a fork of Gnome 2 and it really looks very intuitive and easy to use. If some software conflicts with the MATE environment, a pop-up message will appear on your sceeen and, if you have the patience to read the Details contained in it, you will able to solve your problems. In my particular case (don’t ask me why) it helped me to focus my attention on Conduit which caused the crashes on Gnome.

To easily install MATE, on almost every Linux distribution, you can read its wiki dedicated page or directly follow the below instruction if you use Ubuntu 12.04.

- open Terminal and type these command lines:

sudo add-apt-repository "deb http://repo.mate-desktop.org/ubuntu oneiric main"
sudo apt-get update
sudo apt-getinstall mate-archive-keyring
sudo apt-get update
sudo apt-get install mate-core
sudo apt-get install mate-desktop-environment

When the Terminal finishes all the upgrade stuff, reboot your Ubuntu 12.04 and select MATE on the login screen (click on the upper right “gear” and choose MATE).

That’s all! Have a good week! AddThis

Recovering deleted files from USB disks on Ubuntu

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Everyday we use USB keys to transfer data without transmitting them through the t. The USB keys and portable disks are small, light and their data capacity allow us to move in privacy huge files. This idyll sometimes is broken by a fatal mistake: we unintentionally delete an important file. Normally, if we are smart we recover the erased file in the Trash but in other situations when we realize the mistake we had made is too late.

In this circumstances is very import to stop to use our USB key or portable disk till we are able to use a good software for data recovering. On Ubuntu you have a wise number of dedicated software that can do this job for you, the most powerful run on Terminal as testdisk, foremost, and scalpel but you can also use a “minimal GUI” software as PhotoRec.

PhotoRec is very intuitive to use and it is able to recover many data formats from jpeg to db. After you install it using Synaptic Package Manager or the Software Center you can launch it in Terminal with:

sudo photorec

Immediately a GUI Terminal interface appears and you have just to follow the instruct  ions you visualize on your monitor.

Using the arrows and the Enter keys you have to:

1 – Choose the USB device from where you want to recover the data

2 – Select the partition table (usually Intel)

3 – Specify the partition table

4 – Select the right filesystem where the data were stored

5 – Decide if you want to try the data recovering from all the free space

6 – select the directory where you want to store the recovered data. IMPORTANT: do not store the recovered data on the same USB key you are scanning for recovering

7 – Wait till PhotoRec finishes the recover operations.

PhotoRec is fast and, during our tests, we were able to recover almost the 100% of data. Not bad!!! AddThis

How ro repair Ubuntu 10.04 LTS if the Update Manager and Synaptics don’t work

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After I installed some new software I wasn’t able to update Ubuntu 10.04 LTS. The Update Manager was not able to check for updates and when I tried to use the Synaptic Package Manager I hadn’t better results. A reboot was not the right solution and I tested different ways to solve my problem saving the Ubuntu installation in my computer.

Searching on internet I discovered that there are few possible solution to avoid this problem and, in case you have the same bug on your computer, I decided to sum-up the most powerful after I successfully tried them.

First of all you can try to force the update process through the Terminal typing:

sudo apt-get update
sudo apt-get upgrade

If this doesn’t work you will try with this next step:

sudo rm var/lib/dpkg/lock
sudo dpkg --configure -a

Then launch again the Update Manager to verify if you succeed and if nothing happened solve the matter typing:

sudo rm /var/lib/apt/lists/* -vf
sudo apt-get update

and try again to launch the Update Manager.

In my case this was enough to restore all the Update Manager features and solve the problem. If you have extra problems about this bug or if you want to suggest alternative solutions, please, don’t hesitate to comment this post. AddThis

A new multimedia open-source standard to replace DVD and Blu-Ray DRM limitations: Lib-Ray

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At the beginning we astonished because the video quality on DVD was something of incredible. Then Blu-Ray destroyed all the standards we were used to enjoy while watching our movies. During last 7 years the home theatre industry has developed its standards in a geometric way but the DRM topics have increased our technical barrier between people who legitimately bought DVDs and Blu-Rays and the possibility of creating backup copies.

The war between DRM and hackers is absorbing. When a new standard of DRM has been developed we wait to know how much time will pass before someone can crack it. And it is only a matter of time because it is not technically possible to create the perfect barrier against multimedia supports when, by definition, the key to decrypt the files is somewhere in the disk or on the media player. During last years, the reverse engineering has increase the chances we have to deeply understand and rewrite proprietary software.

Lib-Ray is a “new” ambitious project to create a new open source multimedia standard which could be able to challenge DVD and Blu-Ray. The developers describe Lib-Ray as “multimedia website on a disk”. The manual you can download from Lib-Ray websites, describes in details all the structure you have to create on the disk for your files. Lib-Ray runs on java libraries and html5 structure and its framework is represented by Inkscape, Gimp, Audacity, xiph.org, Flac and code from Mozilla and Chromium.

In few words, you don’t need a specific hardware to run Lib-Ray disks but each computer with a Chromium browser and a bunch of open source software will be able to perfectly play your disks (as simple as genial!).

Last but not least, on the Lib-Ray website you will also find a Downloads page dedicated to dedicated manuals, libraries and one interesting template. AddThis

Searching a Gmail notifier for Ubuntu 10.04… an unpredictable Odyssey!

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Finding a versatile Gmail notifier for my laptop seemed to be not so difficult and, after a first quick search, I selected a bunch of software I believed interesting. But when I tested them I was not satisfied by they behaviour especially because they didn’t have many of the features I wanted.

First of all I started installing the Gmail software I found in the Screenlets repositories on my Ubuntu but it was not able to update itself. Probably the firewall denied to the screenlet to communicate externally. I didn’t want to spend much time (sic) on the research of a Gmail notifier so I decided do uninstall it.

My second option was Popper and reading the program description I believed tha t was really the right one but.. after the configuration I was not impressed by the final flexibility and interaction this software offers. Just to know, for a quick configuration you need Popper configurator that is in the

The next step was represented by KCheckGmail that is for KDE and runs properly also on Gnome but, in this case, the program is not updated with the last Gmail configuration parameters and so it is nice but useless..

Then I tried with Gmail Notify. The configuration is quick and easy but it offers poor results. I mean that you have just the subject of new emails and no possibility to visualize them with a simple mouse click if you haven’t previously done the login of your Gmail account using the browser.

Finally I installed cGmail through the Ubuntu Software Center and I found what I was looking for: a simple program which let me know about new emails and let me open them with a click. The graphic interface is basic but after a couple of hours wasted on searching an effective solution I was satisfied!

Last but not least, if you don’t want to install a Gmail notifier directly on your Ubuntu, consider to install the add-on Gmail Watcher  on Firefox.

Please, if you have better solution and you want to share them with us, don’t hesitate to comment this post. Thank you! AddThis

How to correctly configure and use the Windows Network on Ubuntu 10.04 LTS

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At the beginning it appeared as a no-solved mystery because in all the many posts I read, there were no effective solutions. On my Ubuntu 10.04 LTS I was no able to use the external hard disk I had connected to the LAN and every time I tried to mount it I only received this message: Unable to mount location – Failed to retrieve share list from server


In few words it was not possible to use the Windows Network and all the people with the same problem (which is specific for the Ubuntu 10.04) suggested to reconfigure Samba but all the configuration and scripts I tried were no effective to let me use the external hard disk.

At the end I found someone who talked about a possible firewall misconfiguration and I tried in many ways to bypass the situation using ufw commands and opening ports and services over the LAN:

$ sudo ufw status
[sudo] password for *****:
Status: active

To                                      Action            From
–                                        ——                —-
135,139,445/tcp           ALLOW       Anywhere (log)
137,138/udp                  ALLOW       Anywhere (log)
Samba                             ALLOW       Anywhere
192.168.0.3 Samba     ALLOW       10.0.0.0/8
10.0.0.0/8                    ALLOW       192.168.0.3 Samba

Unfortunately, every new permission I granted to Samba on my Firewall was not a real solution but when I tried to stop the Firewall (System –> Administration –> Firewall Configuration) using the default firewall manager, Ubuntu was able to find and work on the external hard disk.

For this reason I made some tests and found this solution:

1 – enter your router settings and find the list of the attached device

2 – find the name and the MAC address of the LAN device you want to connect to your PC

3 – find the menu for the Lan Setup and add an Address Reservation for the above device. Now you are sure that the router will always assign the same address to the device

4 – back to Ubuntu, install and launch Firestarter (for some incomprehensible reasons the default firewall manager is not able to create rules for Samba services and ports)

5 – on Firestarter, go to Preferences —> Policy Editor and click on “Apply policy changes immediately”

6 – try to connect again to Windows Network, obviously (sic) it will not work but then go to Firestarter —> Events and you will notice that the last line is the “missing” external disk which has an “unknown” service

7 – right-click the mouse on this line and “Allow connections from source”. Now the external hard disk is visible from Ubuntu 10.04 LTS and it is possible to work on it!

8 – to be sure that your LAN device will be rightly connected to Ubuntu 10.04 every time you boot up it: go to System –> Preferences –> Startup Applications

9 – add a new Firestarter rule typing the following command: sudo firestarter

That’s all! I hope you can find this post useful! AddThis

Changing the default text editor on Ubuntu

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There is a few software that will use the editor command to find out what text editor to use. Example commands will be dch to add a new .deb changelog entry, revision control softwares when prompting for commit a message …
There is basically 2 ways for changing the default editor:

1. System Wide
Run Terminal and type:
$ sudo update-alternatives –config editor
And then choose whichever editor you want to be default.

2. User Level
As a user, you cannot change the setting for the whole system, but you can add an alias for editor to let say vim.
Open and edit ~/.bashrc and add:
alias editor=vim
Next time you will open a bash prompt, your default editor will be vim. AddThis