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Screen Calibration on Ubuntu 12.04 with Spyder2 [workaround] May 6, 2012

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The bad news: the default colour calibration wizard on Ubuntu 12.04 has a bug: awful magenta cast on some screens. Fine on others.

The good news: it works flawlessly using the (graphical) alternative below.

As a enthusiastic photographer (see my latest Perl Fosdem pictures) I am very positive about the colour management integration in the latest Ubuntu (12.04). Sure, colour calibration was possible before, but now it’s an integral part of the system and not a simple add-on. Ubuntu++

Once the reviews are in, I will probably buy the ColorHug open source hardware calibration device. In the meantime I borrowed an old Spyder2 (express) from my father-in-law. I do not recommend buying new devices from Colorvision. The company is known to be very antagonistic to free and open source software. But, if you already have the hardware in a drawer it’s better to use it.

Once you plug in the device, the “Calibration” button will activate and the necessary packages will be installed. However, for this HOWTO it’s easier just to install the software (and its dependencies) from a shell window:

$ sudo apt-get install gnome-color-manager

(This install argyll as a dependency that does the real calibration beneath the GUI.)

This step is only applicable if you have a Spyder 2 device. As mentioned above, the company is not FOSS-friendly and doesn’t even provide technical specifications. You will need the firmware of the device from the Windows driver. If you trust me, you can get mine here [MD5: 007ac5705a3a8ed7edf01569700e6ebf]. Put it in the .local/share/color directory in your home directory (create the needed directories if not present). It was extracted from the 2.3.6 Windows driver for the Spider2 Express (the latest at the time of writing). If you want to create the file yourself, see here. In short: you’ll need the driver CD. If you don’t have it or want/need a more up-to-date version, you’ll need to install the driver and feed the generated .dll to spyd2en: spyd2en -v ./CVSpyder.dll

In the GUI (Dash -> Applications -> Color, or simply type “color” and click the icon), if you select your screen and the “Calibrate…”, the steps offered by the wizard are straight forward. Very easy. While it worked great on the computer of my better half, the generated profile on my own laptop (attached to an external screen) had a terrible magenta cast. Not of the type “your eyes will adapt to it”.

After investigating and looking closely at the profile, it was clear that the profile used a 6500K white balance, instead of the 5000K requested in the wizard (it’s called “Photography and graphics” there). Furthermore, the wizard offered 3 calibrations options: 4, 10 and 20 minutes depending on the desired accuracy. While I chose 4 minutes for testing purposes, the calibration took a long time (an hour or longer). Also, the advanced output in the calibration window (hidden by default) categorised the screen as CRT while it’s a LCD. Because of this, I don’t think the problem is tied to the specific firmware (running the latest available) of the hardware, but rather to gnome-color-manager integration with the device and maybe certain configurations. I don’t have other calibration devices available to test. Bug reported.

dispcalGUI is a OS-agnostic alternative to gnome-color-manager and in fact – just as gnome-color-manager – and GUI on top argyll. Just download the deb (the most recent deb for Ubuntu 11.10 works fine on 12.04). If you double click it, the Ubuntu Software Manager will launch and perform the installation (or just use “dpkg -i” if you are a Debianista at heart).

Now, launch the dispcalGUI application from the Dash or just open a terminal (Ctrl + Alt + t) and type:

$ dispcalgui

Select the Photography profile, your screen (if you have a multi monitor setup) and probe your device (by clicking on the “recycle” arrows) and give your profile a more recognisable name and a location. I use brand_model_calibrationDevice, e.g. Samsung_SyncMaster2443FW_Spyder2Express). Click on Calibrate and Profile and go read a book or take some pictures (it will take a lot longer than 20 minutes, probably an hour). If you wish you can skip the white point and black level, YMMV.

Now go back to the Ubuntu Color Settings as above and add the new created profile by selecting your screen, then click “Add profile”, select other and choose the path you save the monitor profile.

Your monitor is now calibrated!

Perl devroom @FOSDEM2012: photos April 27, 2012

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Finally I found the time to “develop” my Perl dev-room @ FOSDEM 2012 pictures (convert from camera RAW files to jpg). It was a very nice event. If you missed the Perl dev-room in the past year, you should really visit us in 2013. Or even better, give a talk.

In the pictures above you see Nicholas talking about Moose. He forgot his mac-VGA adaptor (ahum) so he ended up writing code on the blackboard (“the loudest syntax checker on earth”). Marc mixed some Haskell in his talk while Flavio showed some Javascript-powered Perl. Clément presented a Perl SSO solution and Erik showed us a open source accounting solution. Stefan introduced the PerlCommerce platform, while Ævar (a famous guy being the most mentioned name in Programming Perl, 4th ed!) talks about git-deploy (or rather git-undeploy :) ). Marius explained the marriage of Moose and MemCached.

As the organizer of the Perl dev-room, I had to attend to a few things during the talks. My excuses for not taking pictures of Mark’s and Guillaume’s talk (I was able to attend most of it, though). Sadly,  I didn’t had the time to photograph our fabulous Perl stand (although I have some pictures from last year): Wendy, Liz, Eric and all the other volunteers did a great job.

Thank you for a successful Perl FOSDEM presence.

The Program was as follows:

Welcome to the Perl devroom Claudio Ramirez AW1.121 09:00-09:05
Moose Primer Nicholas Perez AW1.121 09:05-09:25
Advanced Moose Techniques Nicholas Perez AW1.121 09:35-09:55
Perlude: a taste of Haskell in Perl Marc Chantreux AW1.121 10:05-10:45
Perlito Flávio Glock AW1.121 11:05-11:45
The LemonLDAP::NG Project Clément Oudot AW1.121 11:55-12:15
LedgerSMB: Open source accounting running on Perl Erik Huelsmann AW1.121 12:25-12:45
Modern PerlCommerce Stefan Hornburg AW1.121 13:25-14:05
Rapid real-world testing using git-deploy Ævar Arnfjörð Bjarmason AW1.121 14:15-14:35
POSIX::1003 Mark Overmeer AW1.121 15:00-15:40
The FusionInventory Project Guillaume Rousse AW1.121 15:50-16:10
Using Moose objects with Memcached Marius Olsthoorn AW1.121 16:20-16:40

Review: #tweetsmart by J. S. McDougall (O’Reilly Media) March 22, 2012

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Ok. I am new to twitter (@nxadm) and I am not sure I completely grasp the concept. So what’s more promising than a title in the form of a hashtag? The back of the book reads: “#tweetsmart provides the answer [to what to do with twitter] with 25 creative projects to help your business, cause, or organization grow. But this isn’t just another social media marketing book—it’s the anti-marketing how-to community-engagement book”. Does the book deliver? Well, it all boils down to who you are.

The good

It’s certainly a good read. I enjoyed it. It’s short (100 pages), sometimes funny and always extremely to the point, something I appreciate. McDougall is really passionate about the subject and that shows: the author’s style is enthusiastic and upbeat. If you’re a business you’ll be using the oldest marketing tricks in a digital jacket in no time. You’ll reach a much bigger audience that you thought it was possible and it will cost you peanuts. Good.

The bad

So, what if you not own a business? No problem, the back says “business, cause, or organization”, you may think. Nope. Being an free and open source enthusiast involved in a few projects (e.g. Padre, the Perl IDE) it was specifically the “cause or organisation” part that made me curious. Of the 25 recipes, isn’t there at least one applicable to smaller (not commercial) open source projects? Sadly, no. It will help you to sell coffee or burritos, but not reach new users or developers. Did I learn something I didn’t know? Again, no (I repeat: I enjoyed the book).

So the “anti-marketing how-to community-engagement book” epithet may be a little euphemistic. Let’s stick with a “not-annoying and not insulting practical online marketing book for small business”. Sure, it sounds less “cool”, but take it from me, “not annoying and not insulting” part is worth *a lot* when talking about marketing.

Conclusion

Will I recommend it? Well, it depends on who you are. The 3 of 5 stars I give to this book is just an average: it ranges from totally irrelevant for some uses to a fantastic HOWTO to get the online marketing of your business started in no time. You Mileage -May- Will Vary.

#tweetsmart
25 Twitter Projects to Help You Build Your Community
By J. S. McDougall
Publisher: O’Reilly Media
Released: February 2012
Pages: 106
http://shop.oreilly.com/product/0636920021315.do

Migrate a virtualbox VM to a bigger virtual disk March 18, 2012

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When a virtual machine has limited use, you don’t want to loose too much space. Sometimes, however, you get the size wrong.

In my case, I have a minimal Windows VM on my Ubuntu laptop. Once in a while I test an upcoming Padre (The Perl IDE) release or update a crappy usb device with Windows-only support. Win-modems may be gone, but we still have GPS devices that run GNU/Linux but can only be connected to Windows. (I guess seeing your market-share shrink because of smart-phones is what they call bad karma, TomTom.)

Windows being Windows, adding disks is a terrible experience (what’s up with the alphabet as a mounting point?) and moving a Windows installation to a second disk is a nightmare. Luckily, free software gets the job done:

1. Make sure your guest machine is halted properly. This is specially important for a NTFS (virtual) partition of a Windows VM.

2. Download Ubuntu (It does not matter if you use the 32- or the 64-bit version, other GNU/Linux distribution will work as well). The screenshots are from a Ubuntu 11.10 setup.

3. In the specific VM-settings, add a new disk (to the same disk controller) and a new cdrom. Load the Ubuntu iso in the virtual cdrom drive.

 

4. Make sure the VM boots from the cdrom.

 

5. “Try” Ubuntu. Once Ubuntu is loaded, launch “gparted”.

 

6. Select the old disk (normally the first one, check the size).

 

7. Right on the disk representation and “copy” it.

 

8. Select the new disk from the combo-box on the upper right (check the size).

9. Go to “Device”, choose “Create Partition Table…”. Click “Apply” in the pop-up window.

 

10. Right on the disk representation and “paste” the original disk. Click “Apply” in the pop-up window.

11. Click on the green “Apply tick” on the icon menu to apply the changes. This will take some time. Get some coffee.

 

12. Right on the disk representation and select “Manage Flags”. Enable “boot”.

13. Shut down the Ubuntu Live cd.

 

14. Remove the original disk from the VM configuration (back it up first).

 

That’s it!

Logitech Wireless Trackball M570 on Ubuntu March 1, 2012

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A colleague working in our IT-helpdesk found an old Logitech TrackMan Wheel in his drawer. “Old” as in out-of-production model launched around 2002. The thing was good as new: the trackball was still in his original package and the documentation and CD package were sealed. The person that ordered the thing years ago didn’t get used to it after one try. Lucky me :).

So I gave it a try and wow… I have gone ergonomic! While it took some minutes to kill the reflex to move the mouse around, I got used to the trackball mechanism very fast. When I got home I ordered the heir of this model, the Wireless Trackball M570.

At its arrival, my Virtualbox Windows VM was ready to be booted in order to pair the mouse and the wireless adapter. Sadly, Logitech only provides a MS Windows and Mac OS X binary. Once paired, the interwebs agree on this, the combination works on whatever OS you connect it too.

Big was my surprise, when everything worked out of the box in Ubuntu (11.10). Logitech seem to do the right thing nowadays and the devices are already pre-paired. Letting the pairing to the customer seems medieval when you thing about it. Logitech++.

So, everything works fine. The trackball is fantastic. The only complain is that the scroll-wheel makes a cheap plasticky sound when clicked, and as a UNIX user, it’s something you do often. This new model has 2 additional buttons compared to the original TrackMan. Out of the box, they are configured as Back and Next (e.g. while browsing in Firefox).

I don’t care much about these buttons and not at al for the Back and Next function. They are out of the way, so if you don’t use them, they won’t drive you crazy. Anyway, while they are there, why not give them a shot and assign them a useful task: easystoke to the recue! (“sudo apt-get install easystroke” from the shell, or search for “easystroke” on the Ubuntu Software Center)

I configured the additional buttons as Page Up and Page Down, something I really do use often (I find it easier on the hand than using the scroll wheel). I followed the instructions from the Archlinux wiki. Being a wiki, I copy the short instructions in case it get removed or moved:

easystroke is a mouse gesture application, but it can be used to manage mouse buttons as well. It’s main advantage o-ver btnx is that it’s more versatile. On the other hand, it’s user-based, so any user has to configure it to reflect his own needs.

In order to set up easystroke to manage your extra mouse buttons, you’ll need to do this (example features Back/Forward mouse buttons) : run:

easystroke -g

Go to Preferences tab > Additional buttons > Add, and add any special button.

Go to Action tab > Add action, give the new action a name, as Type choose “Key”, as Details set “Alt+Left” for Back button, “Alt+Right” for Forward button, as Stroke click the proper mouse button (confirm if a warning is displayed), and voilà! Your mouse button is configured.

I add some screen-shots for your comfort that illustrate my specific configuration. Nota Bene: to get Shift+Page Up/Down working (e.g. scrolling in a terminal), you need to add the combo to easystroke.

Be nice to me and I’ll be nice to you (ebooks) February 25, 2012

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I love it when I get a fair deal in this greedy digital world. Paying twice for the same content is something I really dislike.

Besides the content, I like chromatic’s way of doing business: you can freely download the DRM-free pdf of his book (Modern Perl) even if you don’t buy a hard copy. Guess what, I bought the book the day it came out.

Although O’Reilly does make you pay for the electronic content of a printed book you already own, they give you a very fair deal: “Upgrade to the electronic version of any print book you’ve registered at oreilly.com, for just $4.99″.

I just got the DRM-free digital version of 5 O’Reilly paper books I already own and I don’t feel cheated at all. Be careful though not to mix offers like the 5$ book “upgrade” the half price for new releases of books you own. In this case you’ll pay half price of the full ebook price instead of the 5 $.

This is how you make customers happy. Treat me with respect and I won’t mind sending some money your way once in a while.

Perl devroom @ FOSDEM2012 February 3, 2012

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fosdemJust a short reminder of the Perl talks at FOSDEM2012.

The Perl dev-room will be held this Sunday February 5th, from 9 to 17h on room AW1.121. We have a wide range of talks. Some talks target Perl programmers with subjects ranging from a beginner to an advanced level. Other talks don’t focus on the language itself, but rather on projects that use Perl as a building stone.

So please, drop by if you are at FOSDEM…

Room: AW1.121
Sunday 2012-02-05
Event Speaker Room When
Welcome to the Perl devroom Claudio Ramirez AW1.121 09:00-09:05
Moose Primer Nicholas Perez AW1.121 09:05-09:25
Advanced Moose Techniques Nicholas Perez AW1.121 09:35-09:55
Perlude: a taste of Haskell in Perl Marc Chantreux AW1.121 10:05-10:45
Perlito Flávio Glock AW1.121 11:05-11:45
The LemonLDAP::NG Project Clément Oudot AW1.121 11:55-12:15
LedgerSMB: Open source accounting running on Perl Erik Huelsmann AW1.121 12:25-12:45
Modern PerlCommerce Stefan Hornburg AW1.121 13:25-14:05
Rapid real-world testing using git-deploy Ævar Arnfjörð Bjarmason AW1.121 14:15-14:35
POSIX::1003 Mark Overmeer AW1.121 15:00-15:40
The FusionInventory Project Guillaume Rousse AW1.121 15:50-16:10
Using Moose objects with Memcached Marius Olsthoorn AW1.121 16:20-16:40

FOSDEM 2012 Perl dev-room: Call For Speakers December 21, 2011

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Taking place in the beautiful city of Brussels (Belgium), FOSDEM is the biggest free and non-commercial European event organized by and for the community. Its goal is to provide Free and Open Source developers a place to meet (see http://fosdem.org/2012/).

Over the last years the Perl community had an increasing presence at FOSDEM. Last year we managed to have both a booth and a dev-room. We collected an impressive positive return and wish to renew the experience.

Our dev-room request for this upcoming edition (2012) has already been approved (the stand request is still pending but we foresee no problems there). The stand will be open throughout the weekend. The dev-room event will take place Sunday February 5th 2012 , between 9 and 17h. The room itself has 81 seats, WIFI and a VGA projector.

This environment, being a university classroom with raised seats, lends itself perfectly for talks. This is a wonderful opportunity to present your Perl project –big and small– or talk about subjects you care about. We are looking for a variety of subjects on all levels: starter and advanced, generic and specialized, core internals and CPAN. We have 8 hours time, so we have the flexibility of using different time formats: e.g. talks of 20 minutes, more classic talks of 40 minutes or longer (although we learned from experience that longer talks should be split into slices of 20 or 40 minutes).

Please don’t doubt to send a proposal (information about yourself, subject, short description and time needed). If you have several subjects you are enthusiastic to talk about please send alternative proposals. In the case more than one talk is not selected, your proposal will help us when putting the schedule together and even have “backup” talks in case someone cancels. Also mention your time constraints (if any).

Please send your talk proposal by e-mail to the address below before January 11th, 2012. After an evaluation period we will submit a definitive schedule on Saturday 2012-01-21 to the FOSDEM organizers.

Please forward distribute this call as wide as possible (certainly to your local mongers). You can link to this page, url: http://nxadm.wordpress.com/2011/12/21/perlfosdem2012-cfs/.

Claudio Ramirez (nxadm, email: padre.claudio at apt-get.be) and the Belgian Perl Mongers.

NB1: This is a community event without sponsoring. We don’t have the means to pay for your trip and time. If you want to sponsor part of the event, please feel free to contact us.

NB2: We’ll also appreciate volunteers, booth and dev-room. Please tell us your availabilities so we can also prepare a planning for this.

Re: APOD to Desktop Wallpaper September 9, 2011

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I saw markam’s post on the Planet Perl Iron Man –where we are both syndicated– where he posts a short script to use the Astronomy Picture of the Day as a wallpaper… on MS Windows.

Being a GNU/Linux + Gnome user myself, I post a quick and dirty “translation” of the script (e.g. to use with cron).

 
#!/usr/bin/env perl
use strict;
use warnings;
use LWP::Simple;
require Carp;

my $apodbase = 'http://apod.nasa.gov/';
my $dlbase = '/home/mmeyer/Downloads/';

chdir $dlbase or die "Couldnt chdir to $dlbase: $!";

my $content = get($apodbase) or die "Couldn't download image: $!";

Carp::croak 'Content doesn\'t match' unless $content =~ m/<IMG SRC="(.*)"/g;

my $urlend = $1;

Carp::croak 'No url found' unless $urlend =~ m|([^/]+)$|;
my $targ = $1;

my $status = getstore($apodbase . $urlend, $targ);
Carp::croak "Couldn't store image: $status" unless is_success($status);

my @shell_cmd = ('/usr/bin/gconftool-2', '-t', 'str', '--set', '/desktop/gnome/background/picture_filename', $dlbase . $targ);
exec(@shell_cmd);

Perl screencasts June 16, 2011

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My friend Gabor got a rush of energy (aka tuits) and relaunched his screencast channel about Perl. So far he has talked about Padre, Perl 6 and the Perl debugger.

I found this last screencast very interesting. For a lot of people the perl debugger is something mythical, arcane or even something they even didn’t know it exists. Certainly people coming from a UNIX shell scripting background wonder how to do something similar to “set -xv” in Perl. I can tell you already: watching the screencast about the perl debugger have been the most fruitful 8 minutes I have spent on IT this week.

So, subscribe to the channel (a gmail address will do) to keep Gabor’s ego motivated to create more. :)

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