More free online classes – for anyone across the World!

There existed OpenCourseWares from MIT, CMU, Stanford and a host of other Universities. Though the students could take these videos any time they liked, there did not exist a goodonline common platform for the students to discuss and get things cleared.

To alleviate this problem, there has recently been a surge in the number of live-courses offered through the internet. These courses run parallel to the courses offered in the universities meaning it has a stipulated timing. Also there is a common forum where the students get to discuss the problems and pose questions and get them answered. I believe such initiatives are nice since they disseminate knowledge and get it to the screens of anyone who is eager to learn

Some good links are :

Coursera.org : Currently about 33 Universities are offering more than 100 courses in 18 diverse categories

Udacity.com : The 21st century university – offers a range of course – more geared towards computer science, artificial intelligence and others

VentureLabs : Courses on entrepreneurship – how to start off a startup

http://networking.class.stanford.edu/ : Explore the Internet in Introduction to Computer Networks

http://solar.class.stanford.edu/ : Be part of the solutions to global energy demands in Solar Cells, Fuel Cells, and Batteries

Stanford’s Free Online Courses : A host of courses offered through their platform Class2Go

And many more..

Stanford’s Free Online Courses

Solution : “Error: Problem during compilation – ifort not found in PATH.” on Abaqus and Intel Visual Fortran on UBUNTU Linux

I got this error
Error: Problem during compilation – ifort not found in PATH

on Ubuntu (using Intel Visual Fortran compiler and Abaqus 6.11). I was trying to use it with the SIGINI subroutine

I was trying to get the solutions online. I found that this simple hack works. Instead of calling

abaqus job=inpFileName

use

export PATH=$PATH:/opt/intel/composer_xe_ 2011_sp1 .9.293/bin/intel64; abaqus job=inpFileName

This trick was required when I was invoking Abaqus from my Mathematica code (and the problem did not seem to subside even when I added the IFort’s path to my PATH variable)

How to embed a Wolfram Mathematica demonstration in your webpage in 3 easy steps

This is a test post + a tutotial on embedding your Mathematica demos in your web-page !

  • Convert the interactive document into a CDF (Computable Document Format). You can get a number of them in the Wolfram demonstration projects.
  • Upload the document to your server
  • Insert the following snippet of code, to point to the uploaded CDF file and you are DONE !
    [html]


    [/html]

A demo

References

http://www.wolfram.com/cdf/adopting-cdf/deploying-cdf/web-delivery.html

There is a WordPress CDF plugin. Check it out here

Ubuntu – how I installed NVIDIA graphics card on Ubuntu 11.04

– GTX – http://www.nvidia.com/object/product_geforce_gtx_295_us.html
Goto “Drivers & Download” section : http://www.nvidia.com/Download/index.aspx?lang=en-us
– download the latest drivers –
NVIDIA-Linux-x86_64-290.10.run
make it executable
– connect the card
– reboot
– goto terminal
– install it sudo ./<filename>
sudo ./NVIDIA-Linux-x86_64-290.10.run
– disable the current graphics card ? Nouveau (yes)
– then reboot (sudo reboot now)
– the old graphics card disabled
– then install
(some installation related notes :
[Nouveau – current grahics driver – had to be disabled before installing the NVIDIA driver]
“modprobe config file to disable Nouveau = etc/modprobe.d/nvidia-installer-disable-noveau.conf – has been written”

“to re-enable nouveau -> delete file etc/modprobe.d/nvidia-installer-disable-noveau.conf”

“install 32-bit compatible installations?” – yes

X configurration file – backed up

– reboot

How to clear DNS cache in Ubuntu?

 

In ubuntu if you want to flush DNS cache you need to restart nscd daemon Install nscd using the following command sudo aptitude install nscd Flush DNS Cache in Ubuntu Using the following commands

(Install nscd using the following command)

sudo aptitude install nscd

Flush DNS Cache in Ubuntu Using the following command

sudo /etc/init.d/nscd restart

 

The equivalent of this no Windows is ipconfig /flushdns

References : http://superuser.com/questions/134762/how-to-clear-dns-cache-in-ubuntu

TiddlyWiki – useful tips – archiving/compressing the backups

In case you are new to this word TiddlyWiki, in short, it is a

Here is an introductory post about TiddlyWiki. And here is a sample of getting organized – a (long but) one-liner to include your Google Calendar in your TiddlyWiki (or in any other HTML page you wish)

I find myself using TiddlyWiki a lot these days. I have the Autosave and SaveBackups options enabled (since I use a desktop which is not on a backup power). Now that my TiddlyWiki has grown to about 1.3MB (!), and the backups are not incremental (by default) (I have not got time to explore the plugins that can do incremental backup of TiddlyWiki), each of my backup is about 1.3 MB. I edit my TiddlyWiki 20 times a day, on an average, which amounts to about 20 * 1.3 = 26Mb a day.

I did not want to trash these backups. I was trying out the various compressions including zip, .ar, .tar, gz, tar.gz and .7z on this.(I am on Ubuntu 11.04 and these come preloaded).

To my amusement I found that the .7z (7-Zip compression) (which is publicly available under the terms of the GNU Lesser General Public License !), gives an amazing compression ratio of about 1000 (THOUSAND! . i.e ) (as can be seen in the following output from the archive manage’s Archive > Test Integrity). In this case, the original size was about 108MB and the compressed size if about 314.9KB!. So I just archive them in 7Z format and dispose the trash files!

PHP on Linux (Ubuntu 11.04 – Natty Narwhal)

These are some of the codes that helped me getting started in using Apache server on Ubuntu 11.04 (Natty Narwhal)

Finding out the user group

 <?php
// outputs the username that owns the running php/httpd process
// (on a system with the "whoami" executable in the path)
echo exec('whoami');
?> 

(often it is www-data )

source : http://php.net/manual/en/function.exec.php


Check you have the permission. If not change the pormissions for the var/www folder on Linux (in case of a 403 error)

If you make /var/www writeable by its group and add the user to the group, that user will not have to use sudo. Try this:
sudo adduser <username> www-data
sudo chown -R www-data:www-data /var/www
sudo chmod -R g+rw /var/www
The user should then be able to edit /var/www/ files without hassle.

The first line adds the user to the www-data group, the second line clears up any files with messed up ownership, and the third makes it so that all users who are members of the www-data group can read and write all files in /var/www.

source : http://askubuntu.com/questions/19898/whats-the-simplest-way-to-add-files-to-var-www


Location of the Apache error log :

/var/log/apache2/error.log

Quickly access the last few lines of the Apache access log tail -f  /var/log/apache2/error.log

http://php.net/manual/en/function.exec.php
http://php.net/manual/en/function.exec.php