BIS-Train Journey Assignment
Me: Hi Alok! How are
you?
Alok: I am fine thank you. How are you and how is your life
after joining VGSOM?
Me: Ah! It’s great. I
am learning a lot of new and exciting things. Yesterday there was a lecture on System
Architecture. I found it quite interesting.
Alok: System
Architecture! Sounds interesting to me too. Tell me more about it.
Me: Well, System
architecture is about data and applications used in an integrated system. The
first principle of integrated system is that data and applications must be
logically distinct from each other even if they are on same physical hardware.
Alok: What is an application?
Me: An application is a computer software used to perform
specific tasks. It processes data according to given command and displays result.
In short it makes our life very easy otherwise we will have to process data
manually. So I was telling you about system architecture. There can be One-Tier
architecture, Two-Tier architecture, Three-Tier architecture or Multi-Tier
architecture.
Alok: Go ahead , I want to know more about all these types
of architecture.
Me: In One-Tier architecture data and application reside on
same physical hardware. It is the simplest of architecture.
Alok: Something like our personal computers where all our
data and applications are present.
Me: Yes I agree. But we are a part of multi-tier
architecture now. Gradually you will understand. In a One-Tier architecture
there is a lot of processing burden on server so the concept of Two-Tier
architecture came. In a Two-Tier architecture data and application are present on different
systems. It is also called “Client-Server” model. The data is stored in a central server which
can be accessed by different clients. The server and clients are present on a
single LAN. Server application can be Oracle or mySQL etc. , while client
application consists of business logic.
Alok: Ok but what was the need for Three-Tier architecture?
Me: Good Question. In a Two-tier system it is very hard and
time consuming to update software as it has to be done on all the client
machines.
Alok: Why do we need to update software?
Me: In this ever changing environment business rules keep on
changing and that demands new software. So in a Three-Tier architecture
application is partitioned in two parts. One part consisting of business logic is kept centrally on a server and other part
consisting of presentation logic is kept locally on client machines. So in case
of change of business logic , application on central server needs to be
changed. Client machines are not disturbed.
Alok: I see. Breaking of application in two parts makes it
easily manageable.
Me: Exactly, that’s why nowadays, Multi-Tier architecture is
used in which application is broken into many parts. Change in one tier doesn’t
affect working of other tiers.
Alok: Can you give me one example of a Multi-Tier system?
Me: Of course, the
omnipresent INTERNET is the best example. In this all the business logics are
interfaced with a web server which can be accessed using a web browser by
clients. But there are serious security threats. That’s why business
organizations use security softwares to safeguard their interests. For personals
computers there are firewalls and anti-virus programs
Alok: As there are different portioning of application
software, can there be different databases?
Me: Of course there can be different databases. But in
general corporate entities use integrated data base because managing data on
different platforms becomes very difficult.
Alok: What sort of difficulties are possible?
Me: There can be redundancy of data which will create
confusion for different departments. That’s why integrated data bases are preferred
worldwide as it ensures there is no duplicity
and inconsistency of data across different locations or time periods. Moreover,
Integrated data base is easier to maintain in view of backup and restore and
security and user authentication processes.
Alok: My God! Internet seems so easy to use but it’s so
difficult to manage.
Me: Internet is managed properly that is why it is easy to
use. I think your destination has come.
Alok: Yes you are right and thanks for the huge amount of
useful information you provided. See you soon.
Me: You are welcome. Bye.
Alok: Bye.
