Playing with Technology (PWT) - Reach Alice's Website !

Hey folks,

This is my first series called "Playing with Technology (PWT)". I will post an interesting real time question related to some technology for you to play around with. It will involve anything and everything i am familiar with. You may have to write scripts, perform hacks, etc. There are no rewards involved. It is just to share the minimal knowledge i possess in the form of an interactive series.

PWT will kick off today with a very simple real time hack that i call as "Reach Alice's Website". Go ahead and enjoy the hack.

Scenario

Alice (yes, our same good old friend Alice) owns a website. Recently, her website was acquired by Hackers World Inc. (http://www.fakehackersworld.com). The CEO of Hackers World considers this acquisition as a very confidential one and decides that all traffic to Alice website should only come through Hackers World website. But the sad part is that, Hackers World website is accessible only to the employees of Hackers World. Your goal, being a hacker, is to somehow reach Alice's website through Hackers World website and acquire the secret key from there!

Alice's Website: http://foamsnet.com/pwt/visit_alice_site
Hackers World Website: http://www.fakehackersworld.com

Remember clues can be lying/hiding in anywhere!

Once you find the key, Post it as a comment in this post. I will approve all the comments once i reveal the answer and will aggregate all the correct responses along with the answer.

Update: The solution has been posted here

-Vignesh

Madarasapattinam and Me !! :-)

I was sitting all alone in podanur railway station (podanur is to coimbatore is what tambaram/perambur is to chennai) awaiting my train to chennai. I had arrived an hour early than the scheduled time just to know that the train was late by half an hour, leaving me a solitude wait of one and half hours. I really liked the peaceful environment with gentle breeze flowering across my face. If I was like before, I would have just been irritated that i would have to wait alone for one and half hours. But then, I had all the feelings about the past awesome six months rushing up to me. And I was involuntarily forced to open my blog and start sharing them. As the title suggests, people who aren't interested in me lamenting about stuff I like and stuff I'm gonna miss, please feel free to press Ctrl+W (frankly I know that you don't really care if I miss velachery railway station or not)

Long story short

Past six months have been awesome and I have really been at the efficient frontier of my life. But sadly, everything has to come to an end. The internship is about to end in a few days and I already couldn't stop feeling bad about the things I'm gonna miss. On the whole, I will miss chennai, I will miss efficient frontier and I will miss everything that has been keeping me going for the past six months.



Short story long

It just seems like yesterday that I stepped into the seventh floor of chamiers towers (well known as satyam building), but all of a sudden, six long months have passed in a jiffy. There have been many life cheering moments over the course of this internship.

I have had many wonderful moments. A bulleted list won't hurt after all:

• The daily bike rides to office! (13 kms one way)


• Breakfast at the near by mess!


• Velachery Sangeethas T20 (the offer still continues as T30 - velachery folks, dont miss it!)


• 5 working days = 5 different cuisines for lunch (Andhra, Punjab, China, Italy, Delhi, Tamilnadu)


• Heavenly mini noon naps in bean bags!


• Non-stop free flowing discussions about work!


• Non-stop fun in the entertainment area (more on the upcoming post..)


• Besant Nagar Beach with friends in the evening!


• Dinner daily at some random shop!


• Maintaining accounts (thinking before every swipe of the card and every rupee out of the wallet)


• And of course the work!


• Fighting online for tatkal tickets to and fro home for long weekends!


• Listening to songs almost 8 hours a day

Another such lamenting is coming up soon!

-Vignesh

Festival of lights is here !! :-)

Hey folks,

The festival of lights is here. We are all gearing up to celebrate the death of narahasuran in a high fashioned manner after these many decades. I just want to take this time off and wish you all a very happy deepavali.



Here is a small one for all the rajinikanth dudes!



இனிய தீபாவளி நல்வாழ்த்துக்கள். இந்த தீபாவளி தினத்தை உங்கள் சுற்றார் மற்றும் உறவினர்களோடு கொண்டாடி மகிழுங்கள்.

-Vignesh

Doodle it up - My first google chrome extension !! :-)

Google is really a part and parcel of our daily life. It has become so inevitable to our daily lives. I have taken a bit of my time to quickly develop a simple Google Chrome Extension to customize your daily visits to google. Wouldn’t you love to see your own picture instead of the boring google logo everytime you open google’s homepage? Yes. This is exactly what this extension does.

Here are step-by-step instructions for installing the extension:

• Download the extension from here


• Install the extension by clicking "Continue"


• Confirm the installation by clicking "Install"


• You will see the confirmation message


• Goto chrome://extensions and click on options under "Doodle it up" extension


• In the page that opens up, enter the URL of the image and then click on Save Settings


• Now, goto Google and Voila! you have your own image instead of the Google logo!

Please post your comments/suggestions as comments.

-Vignesh

Happy Birthday APJ Sir !! :-)

Today is the 77th birthday of the people's president of India, Dr.A.P.J. Abdul Kalam. He is a dreamer and wants to see India as a developed nation by 2020.

You have really been a friend, philosopher and guide for the entire generation of youth in India. We love you sir!!

HAPPY BIRTHDAY!!




Here are a few of his inspiring quotes:

• As a child of God, I am greater than anything that can happen to me.


• Be more dedicated to making solid achievements than in running after swift but synthetic happiness.


• Climbing to the top demands strength, whether it is to the top of Mount Everest or to the top of your career.


• Do we not realize that self respect comes with self reliance?


• Educationists should build the capacities of the spirit of inquiry, creativity, entrepreneurial and moral leadership among students and become their role model.


• English is necessary as at present original works of science are in English. I believe that in two decades times original works of science will start coming out in our languages. Then we can move over like the Japanese.


• God, our Creator, has stored within our minds and personalities, great potential strength and ability. Prayer helps us tap and develop these powers.


• Great dreams of great dreamers are always transcended.


• I was willing to accept what I couldn't change.


• If a country is to be corruption free and become a nation of beautiful minds, I strongly feel there are three key societal members who can make a difference. They are the father, the mother and the teacher.


• If we are not free, no one will respect us.

-Vignesh

root - The king of kings - Question (Part 1)

After these many years of linux, i have finally found something that root cannot do but a non-root user can do! Yes, its true and it was difficult for myself to believe this in the first place. Its like the phrase, “I saw binary numbers floating in my dreams, wait a second, i think i saw a two!”.

I have always not liked the fact that root is the king of linux and he never respects anyone else. Of course we need a system administrator who should be able to control the entire system, but at the same time, using a system administrator account should not be considered as dangerous, as many of the linux distros warn me.

Consider a simple case, root executes rm -rf * from a directory that is owned by xxxxxx and permissions set to 700. root will be able to successfully do this as he has no limits (which is the cause of the danger). I feel that root should still respect the permissions and not be able to do this in one step. If he really knows that he wants to do it, first he should change the permissions of the file (say to 720) and then perform the rm. By this, it requires two mistakes to screw up, rather than one. But the point is, root should respect permissions and he should modify the permissions when he clearly knows what he is doing and must not be entitled to do anything arbitrarily.

Now, to the actual topic. Here’s what a normal linux user would think is always true:

user@user$ marry me
fuck off!
user@user$ sudo marry me
with pleasure sir!

The point of the above statements is that, no matter what, root can always do anything and everything, unless i recently found one exception. I was able to run a command as non root but not as root.

user@user$ touch foo
user@user$ sudo touch foo
touch: Permission denied

Can anyone figure out how on earth could this happen ? (Yes it is really possible!). I’m posting this as two parts (Question and Answer). I will post the scenario i came up with along with the explanation how it is theoretically correct in the next part. If you know of such a scenario, please share it on comments :-)

-Vignesh

DBMS - The art that is taught as a science !!

Note: This post is not intended for a general crowd of audience. This post rambles on about something that the current college syllabi lack and suggests some changes to improve it. If you are interested in reading the previous sentence, then go on. Otherwise just close this tab and move on with your work instead of wasting time here :-)

We all know that database is a software that is used to store, organize, blah blah blah our data. Any person who is taking up a programme related to computer science would have learnt this definition for a short answer question in his/her database management systems course. After having worked with a database that grows by approximately 40000 rows a day, I now realise that the college level courses on DBMS could do much better than what they actually are doing now.

Insights

How the indian college DBMS courses work? Lets have a quick bulleted list of items that a student does during his DBMS course spanning one full semester.

• Reads through the differences between File Management System (FMS) and DBMS


• Reads about ACID properties and byhearts them for answering in the examination


• Reads about various normal forms (and byhearts them for writing short answers in exam). Almost all the DBMS courses say that there are only 4 normal forms (1st, 2nd, 3rd and Boyce-Codd) and they always omit even the fact that there are actually 3 more normal forms (4th, 5th and the 6th)


• Whiles away time with Entity Relationship (ER) diagrams which is the student's life saver in exams (as there is no such thing as THE right answer, anything that makes sense will fetch you marks)


• Learns basic SQL and does a huge list of CRUD (Create, Read, Update, Delete) commands. The most complex query one writes here involves a query with another inner query


• Argues over whether SQL should be pronounced letter by letter (like an abbreviation) or as SeQueL (like an acronym)


• Reads about and byhearts various types of joins and remembers all of them for writing in the exam with a single example


• Optionally, develops an information management system (famous ones include Library Management System, Airline Reservation System, etc.) at the end of the course, where the actual system will consist of nothing but data entry. This project will, of course, go into his/her resume during the interviews


• Towards the fag end of the course, reads something about how the DBMS does some basic operations internally. Most of the students omit this as it is covered in the last few weeks of the semester when students are busy with some other work

The problem

The main problem lying around here is the difference between theory and practice. The beauty about DBMS is that everything that works out perfectly on theory performs worse in practice. For example, consider normalisation. In theory, and according to college syllabi, Boyce-Codd Normal Form is the best that a database could be designed. But in practice, it might kill the database if it mostly consists of reads (because of the increased number of costly joins even for simple reads).

Almost all the colleges teach DBMS in theory and they never consider the practical aspect. And yeah, developing an information management system over the period of the course does NOT count as practice. The information management systems which students develop as a part of their DBMS course hardly involves more than 10 rows per table. And most of the students develop it in the mindset of deceiving the faculty for marks rather than to actually learn DBMS which is the actual objective. DBMS is all about scalability and hence teaching DBMS in small scale is like teaching something that is totally illogical.

What can be done?

Again, let me make a bulleted list of points that i think can be done to bridge the theory to practice gap that is found in the DBMS courses. I am not an expert in DBMS and these are just my humble views on what i feel could be changed.

• First major change to be done is to teach DBMS in the actual scale in which it is to be used. In the lab classes, don't let the students create their own tables and add 5 or 10 dummy records. Give them a preloaded table with ten lakh rows and make them query against that table. This will make them write better queries naturally as every query is going to take some time to spit out the output they want.


• The above step also makes the student to learn about indexes. Indexes are one thing that is really useful in DBMS (i am in the process of writing an article about database indexes - will be posting it once its complete). None of the courses on DBMS really teach about the practical benefits of indexes. When a large table is given, students will have to define indexes and exploit them in their queries.


• Instead of making students worry about JDBC, ODBC, etc. leave the frontend language to their choice and just lay constraints on the backend DBMS system. For example, don't force them to use Visual Basic, which makes a student focus more on learning ODBC and designing forms rather than designing databases.


• Make the joins practical. Don't just teach the various types of joins for the sake of short answer questions. Make it such a way that the student is really comfortable with how exactly the different types of joins work.


• And for god's sake stop teaching stuff about File Management Systems. We are in an era where there is a group that says even SQL and DBMS is not needed (For more about this google for NoSQL).

Closing thoughts

Database Management Systems are the arteries and veins of any corporate business. Hence, learning the complexity and scale involved in it is really inevitable and important. Making proper use of the DBMS course in colleges would be a real boost to the student's career. If the changes i suggested here are incorporated in a course, then that will definitely also save the time that a student spends on preparing DBMS for interviews.

To conclude, "In theory there is no difference between theory and practice. Whereas in practice, there is". DBMS is more of an art which is being taught in colleges as a science. If this change happens, quality of students being spit out of college every year will become better for sure.

-Vignesh