“Haah!! Engineers are nothing but glorified mechanics!”. She dismissed my futile effort to defend myself in a whiff. She continued - “And now it’s even worse… in two year's time you are going to become a dumb and overrated ‘naukar’, who would boast of being a manager.”
There was no point arguing with her. According to her, the disciplines of art and literature were the only worthwhile fields of study; and the person who has not read Shakespeare was as good as dead! There was no denying the fact that she had a better understanding of the finer aspects of life. She also had a knack of appreciating everything that had an artistic value (after all girls have a very high EQ). I, on the other hand was just a ‘glorified mechanic’ (a male, Indian, IT guy) trying to find some purpose in life by pursuing the over hyped Indian ‘MBA’.
She: “I am telling you… you have flushed two years of your life down the drain!”
I: “But I am sure of what I am doing! I have really thought hard about it. It was a conscious decision.”
She: “Oh really? Then you say that this MBA thing will add some value to what you have already learnt?”
I: “Yes. Definitely”
She: “Okay. Then let’s see what you have learnt in these 10 days as an MBA student. Explain me something you have leant in your class that I don’t know. “
I: “Hmm… let’s see. Well are you interested in computers and the internet?”
She: “Yes!”
I: “Do you want to know how the computer design and architecture has changed over the years?”
She: “Enlighten me!”
I: “Well, let’s start with the basics. You must be having a fair idea about hardware and software. Hardware is the physical aspect of a computing entity. You can see, touch and feel the keyboard, the monitor, the mouse, and even the processor or the RAM if you open up the system box of a PC. These are all hardware items. Now, what is software? We can say that it is nothing but an interface between the machine/hardware and the human users. And the most important software is the ‘Operating system’ which breathes life into the hardware devices and together makes up a computer that is usable by the humans. Popular Operating systems that are used today are Win XP, Win7, Linux, Mac OS etc.”
She: “Ah! I knew all this. What next? What is this architecture thing you were talking about?”
I: “All right. Let’s jump to that. In the very early years of evolution of computers and computing devices, the concept of only single-tier architecture existed. If put in simple words, it means that the applications and the data that the applications worked upon resided on the same machine or the same physical computing entity.”
She: “Wait a minute! What exactly is an application?”
I: “Oh! I forgot to explain that. An application is a software that performs a specific job. For example –the MS office applications like MS word, MS excel etc. An example of the data that these applications create and work upon can be the .doc or .docx files that are created in case of MS Word. Now, in a single – tier architecture, all these data as well as the applications resided on the same machine. I hope it is clear now?”
She: “Yes. It’s fairly clear. But you mentioned that this architecture was existent during the earlier stages of evolution of computers. Is it not followed now? I use my laptop, which I guess, uses the same architecture!”
I: “Yes you are absolutely right! The single tier architecture is fine as long as the applications are meant for personal use and there is only one user at a time accessing the data. And hence laptops or PCs meant for home use and not connected to any network still use the single tier architecture. The problem arises when multiple users try to access the same data. Let’s take the example of a banking system. There might be several bank employees trying to access the account details of a large customer at the same time. Now, is it feasible for all of them to sit at a single terminal simultaneously and access the data at the same time? No! Hence the concept of two – tier architecture came into being. In a two tier architecture, we separate the data and the application and thus form 2 different tiers or levels – one consisting the data and another consisting several terminals running a copy of the same application that will be used to access the common data. The terminals or nodes are connected with each other as well as the data physically by a network which is known as the LAN or WAN. LAN is meant for a smaller network with a limited no of nodes and WAN is meant for handling a large number of nodes spread across cities. And finally, the place where the data resides is called a server. ”
She: “That’s a great idea! I believe all the problems are solved now?”
I: “Ha ha! Not really! New problems started arising now! As all the nodes or terminals now had copies of the application, it becomes imperative to install and maintain those applications on each and every node. Now this required a lot of money, time and effort. So, in order to reduce the effort in managing the applications, commercial ventures migrated to what is called the three-tier architecture. Here, the application was split into two parts and this created a new tier. One part handled the simple user interface which is easy to install and maintain. The other part handled the complex business logic which was stored in a central location and was called the application server. Any maintenance activity for the application now became simple as the changes were only needed in the application server.”
She: “Good! We have already moved to the 3rd tier in no time. Don’t tell me that this has also become out dated!”
I: “Not outdated, but yes… you guessed right. A new multi - tier architecture has also come into existence and has become hugely popular in the recent times mainly because internet browsing has become a day to day activity for all of us. In this multi – tier architecture, we replace the user interfaces on the nodes by a web browser and the LAN or WAN by the internet. Now as the web browser cannot communicate with the application server directly, a web server is introduced in between the internet and the application server as a translator and this introduces the fourth tier.”
She: “But I hear a lot of hacking threats that are associated with the internet. How do the multi – tier architecture tackle that?”
I: “Well, that is also taken care of! Special softwares called firewalls are installed between the webservers and the internet and also between the browser and the internet. This ensures that the hackers do not get an entry point from the internet.”
She: “Hmm… sound interesting. So is that it? Are there anymore tiers??”
I: “At this moment no. But who can tell about what the future holds! However, there are a few variations of the multi – tier architecture. ”
She: “Alright! I think you have done your bit to convince me that you are learning something worthwhile after all. But it was too much ‘gyaan’ for a day! Let’s stop here and go for a coffee shall we?”
“Thank God… saved for the day!”, I thought with a smile and replied - “Yes dear! Why not! Let’s also have your favourite chicken mayonnaise sandwich along with the coffee. I am starving.”
VGSOM, IIT Kharagpur
**MIS - Stand for "Management Information Systems", which is a core course taught to 1st semester MBA students at VGSOM, IIT Kharagpur. This blog post is a part of the innovative assignments (with a special stress on cloud computing) that are given to us as a part of the evaluation process.
