Or see this on YouTube — and yes this is quite ironic that we’ve uploaded to YouTube the visualised history of a streaming software stack.

The video you can see here is the GIT history of feng the RTSP streaming server me and Luca are working on for the LScube project, previously founded by the Turin Politechnic, visualised through Gource .

While this video has some insights about feng itself, which I’ll discuss on the mailing list of the project soon enough, I’m using this to bring home another point, one even more important I think. You probably remember my problems with ATI HD4350 video card … well, one of the reasons why I didn’t post this video before, even though Gource has been in tree (thanks to Enrico) for a while already, is that it didn’t work too well on my system.

It might not be too obvious, but the way Gource work is by using SDL (and thus OpenGL) to render the visualisation to screen and to (PPM) images – the video is then produced by FFmpeg that takes the sequence of PPM and encodes it in H.264 with x264; no I’m not going to do this with Theora – so you rely on your OpenGL support to produce good results. When 0.24 was being worked on (last January) the r700 Radeon driver, with KMS, had some trouble, and you’d see a full orange or purple frame from time to time, resulting in a not-too-appealing video. Yesterday I bit the bullet, and after dmesg has shown me a request from the kernel to update my userland, I rebuilt the Radeon driver from GIT, and Mesa from the 7.8 branch…

Perfect!

No crashes, no artefacts on glxgears, and no artefacts on Gource either! As you can see from the video above. This is with kernel 2.6.33 vanilla, Mesa 7.8 GIT and Radeon GIT, all with KMS enabled (and the framebuffers work as well!). Kudos to Dave, and all the developers working on Radeon, this is what I call good Free Software!

Just do yourself a favour, and don’t buy videocards with fans… leaving alone nVidia’s screwup with the drivers, all of them failed on me at some point, passive cards instead seem to work much longer, probably because of the lack of moving parts.

While clearing out the big pile of emails today, I came across this huge discussion on ubuntu-dev -discuss list about the colours of gnome-terminal. Honestly, I never thought this could be a point of discussion at all , but I was wrong. This article is just a brief summary of that discussion. This might not look of any use but its always good(and a little fun) to know other's opinion about such issues.

Well, lets start with the first mail, complaining about the current gnome-terminal and xterm theme, black text on white background. The guy seemed right with his arguments that historically Linux terminals or command lines in general have always been white text on a black background, KDE still uses them then why not gnome-terminal. I totally agreed with him until I came to know about the term, Ergonomics. I am pretty sure I would have lost most of you here. But carry on, you should know about this stuff.

Ergonomics actually concerns with the study of designing the job, equipment, and workplace to fit the worker(more info on wiki). I knew that gnome guys are crazy about usability but if Ergonomics is the reason for the default theme, then I never really thought that they would go this far to enhance user experience. Hats off to GNOME.

Now, our big question, what should be the colour? seems to be solved. But I still think that people hardly care about what ergonomics says. Common! we are linuxers, we are always curious to find new and better things. Although, I think that gnome devs probably knew that someday, someone will raise a finger on this issue, and so they made the terminal theming highly customizable.

Customizations available in Gnome-Terminal

• Use any possible text colour on any background, say, perky pink on goblin green .
• Your background needn't be a solid colour, it can be an image or even a semi transparent background of any colour.
• You can even create different profiles to manage your themes.

Well, if I were to say my choice of theme, I would go with dark green on black, makes you feel like a H4k3r . Although, now I am happy with the the default theme. Anyway, if you use any of such special or unusual themes, do share. I would like to know about your taste.

/usr/bin/VBoxHeadless

You should have the message below :

Sun VirtualBox Headless Interface 3.1.4
(C) 2008-2010 Sun Microsystems, Inc.
All rights reserved.

Usage:
-s, -startvm, –startvm <name|uuid>   Start given VM (required argument)
-v, -vrdp, –vrdp on|off|config       Enable (default) or disable the VRDP
server or don’t change the setting
-p, -vrdpport, –vrdpport <ports>     Comma-separated list of ports the VRDP
server can bind to. Use a dash between
two port numbers to specify a range
-a, -vrdpaddress, –vrdpaddress <ip>  Interface IP the VRDP will bind to
-c, -capture, –capture               Record the VM screen output to a file
-w, –width                           Frame width when recording
-h, –height                          Frame height when recording
-r, –bitrate                         Recording bit rate when recording
-f, –filename                        File name when recording.  The codec
used will be chosen based on the
file extension

I was looking for a way to easily share documents between machines, since WebDAV shares can be accessed by Windows, Linux or Mac machines out of the box, I choose WebDAV over SSL. I don’t use SSL for anything so WebDAV is served from DocumentRoot. I’ve been using it for a few days, so far it beats carrying USB sticks around.

Enable relevant Apache modules,

<code class=" apache">a2enmod ssl
a2enmod dav_fs
a2enmod <span class="keyword">dav</span>
</code>

Create SSL certificate,

<code class=" cpp"> mkdir /etc/apache2/ssl<br /> openssl req $@ -<span class="keyword">new</span> -x509 -days <span class="number">365</span> -nodes -out /etc/apache2/ssl/apache.pem \<br />     -keyout /etc/apache2/ssl/apache.pem<br /> chmod <span class="number">600</span> /etc/apache2/ssl/apache.pem<br /></code>

Create your WebDAV directory and create a password file,

<code class=" sql">mkdir /path/<span class="keyword">to</span>/webdav/<br />chown www-data /path/<span class="keyword">to</span>/webdav/<br />htpasswd -c /path/<span class="keyword">to</span>/passwd.dav <span class="keyword">user</span><br /></code>

Edit and add the following snippet to the configuration for the host you want to enable WebDAV,

<code class=" apache"> <span class="tag"><VirtualHost *:443></span><br />         <span class="keyword">ServerAdmin</span> <span class="keyword">user</span>@host.com<br />         <span class="keyword">DocumentRoot</span> /path/to/webdav<br /><br />         <span class="keyword">SSLEngine</span> <span class="literal">on</span><br />         <span class="keyword">SSLCertificateFile</span> /etc/apache2/ssl/apache.pem<br /><br />         <span class="tag"><Directory /path/to/webdav/></span><br />            <span class="keyword">DAV</span> <span class="literal">On</span><br />            <span class="keyword">AuthType</span> Basic<br />            <span class="keyword">AuthName</span> <span class="string">"webdav"</span><br />            <span class="keyword">AuthUserFile</span> /path/to/passwd.<span class="keyword">dav</span><br />            <span class="keyword">Require</span> valid-<span class="keyword">user</span><br />        <span class="tag"></Directory></span><br /><br />         <span class="keyword">ErrorLog</span>  /path/to/webdav/error.log<br />         <span class="keyword">CustomLog</span> /path/to/webdav/access.log combined<br /> <span class="tag"></VirtualHost></span><br /></code>

Reload Apache configuration,

<code>/etc/init.d/apache2 reload<br /><br />from <a target="_blank" href="http://nakkaya.com/2010/03/05/webdav-ssl-on-debian/">here</a><br /></code>

HTML4 has served us for more than 10 years now and there hasn't been any major update in it, there is XHTML that has done a little more by making code more strict, if at all you are concerned with HTML compliance. Work on HTML5 was started in 2004 by a group called WHATWG founded by Apple, Mozilla and Opera. Most new browsers are now supporting new HTML5 tags. In this article, we will have a look at some HTML5 features which will make your web development easier and organized.

Structure of HTML5 Tags

The one thing that I like very much about HTML5 is that its designers caught the web trends pretty well. Consider this example of the 'div' tags in HTML4. If you have used them you would know how we use ids and classes to define the structure of a page and identify parts of the page as article, header, footer, section etc.

Looking at the repititive use and popularity of some of the ids, namely, header, footer, nav, article etc. the developers made proper tags out of them.

Canvas

Canvas was first implemented by Apple for OS X Dashboard widgets. Now, its a formal part of HTML5

<canvas width=".." height=".." > </canvas>

Uses of Canvas

• Dynamic and interactive Graphics
• Draw images using 2D drawing API (lines, circle, fills, shapes)
• Useful for graphs, applications, puzzles and games.

Canvas Example graphs

Plotkit: http://www.liquidx.net/plotkit/ JavaScript library, Draws graphs from any data source, such as a table.

Canvas Example applications:

• Yahoo Pipes: http://pipes.yahoo.com/pipes/ Interactive, drag and drop interface
• CanvasPaint: http://canvaspaint.org/ Clone of MS Paint built with Canvas. Could be used to build a Shared Whiteboard application

Canvas Example Games:

Canvex: http://canvex.lazyilluminati.com/ Experimental First-Person Shooter Game, 3D Graphics

Canvas standard API for drawing.

ctx = canvas.getContext("2d");
ctx.fillRectI(x, y, width, height);
ctx.beginPath();
ctx.moveTo(x, y);
ctx.moveTo(x, y);
ctx.lineTo(x, y);
ctx.bezierCurveTo(x1, y1, x2, y2, c1, c2);

and loads of exciting functions

There's no IDE needed for canvas and no plugins required. Canvas gives you an option of making your site high graphics without using flash. It has some performance issues, but its getting better with faster javascript and rendering engines.

Try out some canvas demos

Video and Audio

Due to no support for video in HTML4, many sites relied on flash for audio and video. And it had become a defacto animation standard. HTML5 supports both video and audio tags, its now possible to custom design user interface, start, stop, pause, seek and adjust volume. It provides DOM Api's to control the video and audio playbacks. We can include audio and video using simple tags:

<video src="video.mp4" width="320" height="480" posters="screenshot.jpg" controls />

or

<video id="video" width="640" height="480" volume=".7" controls autoplay>
  <source src="video.mp4" type="video/wmv"></source> (For Browser supporting H.264 codec)
   <source src="video.ogg" type="video/ogg"> </source> (For Browser supporting Theora codec)
</video>

<audio>
   <source src="music.oga" type="audio/ogg">
   <source src="music.mp3" type="audio/mpeg">
</audio>

Based on the Codec which your browser support you can specify alternate video and audio formats.

HTML5 progress and meter tag.

Progress and meter

<progress> tag is used as a conjection to javascript to measure progress of a task.

This shows completion progress of a task, used for indicating loading progress of ajax application.

<meter> Representing scalar measurements or fractional values

Useful for:

• User Ratings (e.g. YouTube Videos) 
• Seach Result Relevance
• Disk Quota Usage

<progress value="600" max="1000"></progress>

  <meter min="0" max="5" value="3"> </meter>

<meter> 2/10</meter>
<meter> 200 out of 1000</meter>

Keygen

<form method="post" action="action.htm">
<keygen name="encryptedInfo" challenge="1234512312" />
</form>

Internet explorer doesn't support this tag, read more.

Mark

This tag should be used as a reference to indicate text as marked/highlighted. Not to be confused with <em>. This tag is userful in indicating relevance and point of interest.

Useful for:

• We can highlight relevant code in the sample.
• Highlighting seach keywords in a document (example forums, and google cache).

<p>The <mark>mark</mark> tag is used for getting your reader attentions.</p>

Time

This tag is used to display date and time within an HTML document.

Microformats datetime-design-pattern in HTML4 has accessibilities issues as they expose machine data to humans by misusing the HTML4 abbr tag. These problems led to the BBC removing Microformats from their site.

<abbr class="datetime"
      title="2007-08-02T23:30Z">
  Fri, Aug 03 2007 at 09:30
</abbr>

This problem goes away in HTML5 as it introduces a time tag which is better than abbr for marking up date and time.

Linuxers was launched in <time datetime="2009-10-07">October</time>.

Our Office close at <time>09:00</time>PM IST.

This solves Accessibility Issue and Can be used in Microformats like hCalendar

Command

<menu type="toolbar">
  <command onclick="insert(0);" icon="bold.gif">
  <command onclick="insert(1);" icon="italic.gif">
  <command onclick="insert(2);" icon="link.gif">
</menu>

Device

The <device> tag allow the user to give access to a device example video camera.

<p>Start chatting, Select your video camera: <device type=media onchange="update(this.data)"></p>
<video autoplay></video>
<script>
function update(stream) {
document.getElementsByTagName('video')[0].src = stream.URL;
}
</script>

Form Controls

In HTML4 form controls are too limited, several new input types are added in HTML5 to remove repeated use of some input types like checkbox and select.

<input type="datetime">

<input type="date">

<input type="time">

<input type="number">

<input type="range">

<input type="email">

<input type="url">

<input list="title-list">

<datalist id="title-list">

  <option value="...">

</datalist>

Form Validation

HTML5 has new validation tags to validate a form for the expected input required, pattern, min, max, etc. New DOM API allow script to detect and deal with user error more easily.

HTML5 and Microformats

HTML5 non-visible data-* attribute is used for embedding data on a page. Many Microformats can make use of these HTML data-* attributes for embedding custom hidden data. An element in HTML5 can have any no of data-* attributes.

<div class="product" data-id="328" data-type="laser" data-shields="20%" data-x="15" data-y="40" data-z="30">

Tags that weren't discussed in this article.

<datalist>, <details>, <dialog>, <embed>, <figure>, <output>

Just read a mail from Alberto Milone, where he mentions the warning issued by NVIDIA that the drivers 195.36.08 and 195.36.03 might be affected by the same GPU fan speed issues which were detected earlier in the windows drivers. You might not face any troubles with it but there have been a few reports so its better to be careful. The problem might take a while to resolve, so its better to take the measures suggested by Nvidia and Alberto Milone(for Ubuntu). Here I have discussed those measures.

According to Nvidia, until the problem is resolved, Linux users should revert to 190.53 web release or the 195.30 public beta. They are going to remove the 195.36.08 and 195.36.03 drivers from NVIDIA's FTP site.

Otherwise, you might want to disable the current suspicious driver, using either of the 2 methods suggested by Alberto Milone in Ubuntu. This might be the case for only Lucid users.

Disable the driver with Jockey

Go to System->Administration->Hardware drivers, disable the Nvidia driver and restart the computer.

Using following commands.

Open a terminal (Applications->Accessories->Terminal) and execute the following commands to temporary solve the issue.

[shredder12]$ sudo update-alternatives --config gl_conf (and select the alternative provided by mesa)
[shredder12]$ sudo ldconfig
[shredder12]$ sudo update-initramfs -u
[shredder12]$ sudo mv /etc/X11/xorg.conf /etc/X11/xorg.conf_old

Now, restart your computer.

Sources: http://www.nvnews.net/vbulletin/announcement.php?a=39
               http://albertomilone.com/wordpress/?p=482

sameone thanks me for the post
Riak combines a decentralized key-value store, a flexible map/reduce engine, and a friendly HTTP/JSON query interface to provide a database ideally suited for Web applications.

and a perfect howto to install it here

google_protectAndRun(“ads_core.google_render_ad”, google_handleError, google_render_ad);google_protectAndRun(“ads_core.google_render_ad”, google_handleError, google_render_ad);

After a fresh installation of Debian Lenny, I wanted to use a quite very recent version of VirtualBox.
One solution is the Debian backports : Here are the VirtualBox packages available
To make VirtualBox work well, you need to install the following packages : virtualbox-ose, virtualbox-ose-qt and virtualbox-ose-source

Here are the version(s) available for each package mentioned above :

virtualbox-ose : 3.0.12-dfsg-1~bpo50+1 (for i386)
virtualbox-ose-qt : 3.0.12-dfsg-1~bpo50+1 (for i386)
virtualbox-ose-source : 3.1.4-dfsg-1~bpo50+1 (for all platforms)

As you may have noticed, virtualbox-ose-source version is higher than the ones above. As a test, I installed all of them. I compiled the modules needed with module-assistant. I failed to launch a virtual machine.
Here is the message I got :

VBoxHeadless: Error -1912 in supR3HardenedMainInitRuntime!
VBoxHeadless: RTR3Init failed with rc=-1912

Running as a normal user the command vboxheadless, I encountered the same message :

fool@localhost:~$ vboxheadless

VBoxHeadless: Error -1912 in supR3HardenedMainInitRuntime!
VBoxHeadless: RTR3Init failed with rc=-1912

VBoxHeadless: Tip! It may help to reinstall VirtualBox.

The only workaround I found for this problem is to install the Sun’s package available here .
To install it :

root@localhost:~# dpkg -i virtualbox-3.1_3.1.4-57640_Debian_lenny_i386.deb

Make sure that the good modules are loaded correctly :

root@localhost:~# lsmod |grep vbox

vboxnetadp              6436  0
vboxnetflt             12332  0
vboxdrv               155144  2 vboxnetadp,vboxnetflt

As a last test, run the following command :

root@localhost:~# /usr/bin/VBoxHeadless

You should have the message below :

Sun VirtualBox Headless Interface 3.1.4
(C) 2008-2010 Sun Microsystems, Inc.
All rights reserved.

Usage:
-s, -startvm, –startvm <name|uuid>   Start given VM (required argument)
-v, -vrdp, –vrdp on|off|config       Enable (default) or disable the VRDP
server or don’t change the setting
-p, -vrdpport, –vrdpport <ports>     Comma-separated list of ports the VRDP
server can bind to. Use a dash between
two port numbers to specify a range
-a, -vrdpaddress, –vrdpaddress <ip>  Interface IP the VRDP will bind to
-c, -capture, –capture               Record the VM screen output to a file
-w, –width                           Frame width when recording
-h, –height                          Frame height when recording
-r, –bitrate                         Recording bit rate when recording
-f, –filename                        File name when recording.  The codec
used will be chosen based on the
file extension