Systems Engineering

It was early morning and I had just gone to sleep after a late night out and my mobile started ringing. My brother Ankur was on the other side of the phone.

Ankur: Bro, I’ve to submit an assignment on System’s Architecture today. I’ve collected some information about it from the net but not being able to understand what is it? Can you please help me out?

Me: Can you send me the data or any presentation which you have collected. I’m going online.

Ankur: Ok, wait a minute.

Me (after studying the ppt): Systems architecture is the design or set of relations between the parts of a system. You can say it is the structure of components, their interrelationships with each other and the environment, and the principles and guidelines governing their design and evolution. The first principle says, “Data is different from the application”.

Ankur: But, where are these two separate entities located?

Me: Let me explain you. First tell me, do you know about tiers in system architecture?

Ankur: No

Me: Hmm… Ok, there are basically 3 tiers of system architecture.

In a single tier, the data and processing are on a single machine (which can be either a desktop, laptop or a server)

In two tier architecture - the client executes on a user workstation, and a database server executes on another node in the network. The presentation is handled by the client and data is stored on and accessed on the server. But the application or business logic can reside on the client or on the database server in the form of stored procedures. The LAN connects client machines to the server using TCP/IP protocols.

In three tier architecture, the business logic is kept centrally and presentation logic is kept locally. To give you an example, a bank’s database at the main head-office contains the user database and basic business application, whereas, all the presentations, which need more graphics and thus, high bandwidth, are done on the client’s machine. Due to this the data transfer over the network is minimized.

In multiple tier, the end-user's browser communicates with Web. All the presentation logic occurs on standard servers.

Ankur: Ok

Me: One thing I forgot to tell you regarding the architecture- as you keep on going from single tier to a multi-tier architecture, flexibility, user independence and availability increases, but the security, manageability and control decreases, which has to be taken care of very carefully.

Ankur: What about the security issues when we use database and its application on different machines?

Me: Yes and now comes the role of a firewall. Internet is a public network and is prone to hacker attacks and to counter this you would require firewalls such as ZoneAlarm, or better still, anti-virus software such as Norton on our system.

Ankur: Thanks Bro, now that I’ve a fair idea about what is System Architecture, I think, I can now make a decent enough project. I’ll let you know if I need some more help.

Me: You are welcome. Good bye and God bless.