Unconventional way of studying things..

Sometimes I think that I studied lot of things in engineering text books, but don't have any clue on how the concepts/formula derived or how much analysis they put behind on those concepts.That research or hacking experience generally missing in text books. Sorry ..I am not saying school/college text books are bad. We ( as students) always needs to read text books .. but what I am trying to convey is... sometimes  textbooks are missing practical possibilities of  formulas or concepts.

There comes the importance of unconventional way of studying things..  or the hackers(in good sense) way of mastering the interested areas. Our schools and  colleges should give these kind of opportunities for students.

 Okay.....

These things came to my mind when I was watching the below video... 





She (http://jvns.ca )  explains the tool 'strace'

I tried 'strace' against our normal linux command 'ls'. This actually listed me amazing tracing log ...

 This is just an example .All concepts that we are studying/hearing should have unconventional way of mastering it or we should at least try to develop it !!!

None of the computer text books might have taught you on, what actually happens behind the 'ls' command. But the unconventional way is, find out some tool which can list the activities behind 'ls' and mastering what is it doing.... obviously it is very difficult, but  it gives you the full concepts behind the 'ls' upto very low/machine level.

Unconventional way of studying things opens opportunities which are not described in most of the text books That gives you the confidence to question the actual concepts or current implementation.

But it will have some initial difficulties and extra research  out of your text books or tutorials. But I am sure that there will be always some supporting tools/methods which somebody might have implemented already or you can implement such a method if it's not there!! :-)

Below is the screenshot of 'strace' on  'ls' in command line

some research on each system calls behind means ..

LXR Cross Referencer to read linux kernel source code

LXR Cross Referencer

This is the best place to refer one who like to know about linux kernel. http://lxr.free-electrons.com/ LXR Cross Referencer, usually known as LXR, is a general-purpose source code indexer and cross-referencer that provides web-based browsing of source code, with links to the definition and usage of any identifier.

I also found the following site is very helpful to start with linux kernels http://kernelnewbies.org/FirstKernelPatch

Installed wireshark for Networking package analysis

WIRESHARK

Wireshark is a network protocol analyzer. This is actually nice tool which gives opportunity to analyze  and understand different network layers. Each packet  traffic is diplayed when we start browsing a website.Its very easy to install in Ubuntu using 'Ubuntu Software center'. After installing I used the command and changed to root. I am not sure any alternative way for getting my 'wlan0' wifi internet without changing to root.

sudo dpkg-reconfigure wireshark-common

started wireshark with 'sudo wireshark'

Planning to learn networking modules in Linux Kernel

I am just writing this blog to make sure that I will refresh my system programming knowledge. Every time when I start motiviated with some concepts , it used to end in a week :-). Now I am going to try Networking modules in Linux kernel. As you all know , linux is like a ocean and any time we can go do some research and learn .. that what I like in GNU/Linux.

I got some tutorials from Youtube to start with the networking modules in Linux kernel.. don't know the opportunities that I am going to get in this. sharing some of the videos below .

Django with Angular js

This is very nice document http://django-angular.readthedocs.io/en/latest/angular-model-form.html ,one django learner should practice to get confidence on his/er django web development skills. I am sure the document gives you good learning experience in web development .

What is Django ?

Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design. Built by experienced developers, it takes care of much of the hassle of Web development, so you can focus on writing your app without needing to reinvent the wheel. It’s free and open source https://www.djangoproject.com/
What is Angularjs?

AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template language and lets you extend HTML's syntax to express your application's components clearly and succinctly.
https://docs.angularjs.org/guide/introduction
http://www.w3schools.com/angular/

GeoDjango opens new opportunities for free and low cost geo application

Since google map matrix has pricing plans, web developers are started thinking of an alternative. I guess, you can use https://www.openstreetmap.org/#map=15/10.2708/76.3780 as an alternative since lot of companies and institutions are contributing for it.

Its quite interesting and innovative idea that Django ( python webdevelopment framework) is coming up with module for geographic web application GeoDjango. GeoDjango is an included contrib module for Django that turns it into a world-class geographic Web framework. GeoDjango strives to make it as simple as possible to create geographic Web applications, like location-based services. Its features include:


Django model fields for OGC geometries and raster data.
Extensions to Django’s ORM for querying and manipulating spatial data.
Loosely-coupled, high-level Python interfaces for GIS geometry and raster operations and data manipulation in different formats.
Editing geometry fields from the admin.

how to build Django admin page

It might be a time consuming and headache to build admin page for website. But the case is so cool with Django :-). I started with Django because I like python language. But its so amazing that you can build some pretty cool things in short span of time.It was a little difficult to start with it,but in my experience its pretty easy thing once you used with it. Below is the tutorial I followed to build the admin page.

http://www.djangobook.com/en/2.0/chapter06.html

Models in Django to create tables

How to connect Mysql database to Django

manged to install mysql database in ubuntu and created some tables using Models in Django.

Below online book is really helpful to master Django- http://www.djangobook.com/en/2.0/chapter05.html

models.py:




Mysql:

Apache Spark installed in Ubuntu

I am not sure much uses of Apache Spark. But thought of installing and play around .
https://www.mapr.com/blog/game-changing-real-time-use-cases-apache-spark-on-hadoop

Successfully installed Apachespark in Ubuntu using the below blog instructions.
http://blog.prabeeshk.com/blog/2014/10/31/install-apache-spark-on-ubuntu-14-dot-04/

This is the beauty of Open Source softwares, you can install it and play around it ..and contribute for the project.

For more details - http://spark.apache.org/

examples - http://spark.apache.org/examples.html

sqllite3 commands in Ubuntu Shell

How to install and use Sqllite3 in Ubuntu: 

Its quite easy to install sqllite3 in Ubuntu using 'apt-get install sqlite3'

naveen@naveen-Inspiron-7352:~/mysite$ sqlite3 mydb
SQLite version 3.8.2 2013-12-06 14:53:30
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .databases
seq  name             file                                                     
---  ---------------  ----------------------------------------------------------
0    main             /home/naveen/mysite/mydb                                 
sqlite> exit
   ...> exit()
   ...> create table employee(id integer,name TEXT );
Error: near "exit": syntax error
sqlite> create table employee(id integer,name TEXT );
sqlite> insert into employee(1,'naveen');
Error: near "1": syntax error
sqlite> insert into employee values (1,'naveen');
sqlite> ;
sqlite> select * from employee
   ...> ;
1|naveen
sqlite> .exit

Django Login Page

After the struggle of 2 days :-), I succeed to create login page in Django with sqllite3. First we need to set up sqllite .. visit this site for more details http://www.saltycrane.com/blog/2007/11/django-project-2-sqlite-setup/

The other issue was , I was keep on getting the 'CSRF cookie not set'. I managed to exempt the CSRF using below technique, but its better use CSRF. http://stackoverflow.com/questions/22812721/why-do-i-get-csrf-cookie-not-set-when-post-to-django-rest-framework
and finally my login page worked !!!!!!!!!!!!

How to create a collection and document in MongoDB

MongoDb installation in Ubuntu