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This is the conversation between me and my friend. Who is also studying in B school.

Me: Hi, Vishal how are you doing?

Me: I am fine, what about you?

Vishal: I am not doing well.

Me: Why, any problem?

Vishal: I have to prepare for systems architecture for my exams. But I do not understand it.

Me: Ok. I can help you with the same. I have just attended the lecture.

Vishal: That’s great.

Me: First of all we need to differentiate between Computer science and Information systems engineering. Computer science is partitioned in to two i.e.Data Structures: describes WHAT is to be processed and Algorithms: specifies HOW it is to be processed

 Information Systems is also partitioned into two types i.e. Data Systems: describes WHAT is to be processed and Application Systems: specifies HOW it is to be processed

Vishal: ok, so the data and applications are the same?

Me: No, One must keep in mind that the Data must be logically distinct from Applications.

Vishal: Ok, there is only one type of architecture?

Me: No, we have different types of application architecture

1)      Single tier:  In this application architecture we are expected to separate the data and applications from each other. Even if they are present on the same physical hardware i.e. laptop / desktop / server.

2)      Two tiers: In this application architecture we separate data and application by separating them physically that is data is on server, which has the different software like Oracle / MySQL / SQL Server / DB2. And different applications are stored on individual machines. There are two  logics of storing in the individual machines one is

a.       Business logic:  those are the business rules

b.      Presentation logic: the GUI : windows, buttons etc

Vishal: What is GUI?

Me: It is Graphic user interface. It is a type of user interface which allows people to interact with a computer and computer-controlled devices. It presents graphical icons, visual indicators or special graphical elements called “widgets”. Often the icons are used in conjunction with text, labels or text navigation to fully represent the information and actions available to a user. But instead of offering only text menus, or requiring typed commands, the actions are usually performed through direct manipulation of the graphical elements. 

Vishal: Ok, go ahead.

Me: Yes, the company access the database by using WAN (Wide area network)

Vishal: What is WAN?

Me: It is a computer network that covers a broad area i.e., any network whose communications links cross metropolitan, regional, or national boundaries.

Vishal:  Is there any advantage of using two tiers instead of single tier.

Me:  There are advantages and disadvantages as well. Advantages are convenient graphics user interface and does not place processing burden on server machine when you have hundreds of users

And the Disadvantages are High Bandwidth requirements: slows down application, Wide Area Network (WAN) issues and Maintenance / Version Control of distributed software.

Vishal: Ok, that’s it?

Me: No we have more,

Three tiers: In this application architecture we separate data and application by separating them physically that is data is on server, which has the different software like Oracle / MySQL / SQL Server / DB2.

But in this,  application is partitioned i.e. Business Logic kept centrally (Changes to business logic done at one location) and Presentation Logic kept locally (Data transfer over network is minimised). They are again accessible by WAN.

Multi tier: This architecture is same as three tier architecture; the difference is that instead of WAN internet is used. It doesn’t require dedicated client but only browser. There is addition of one machine that is called web browser.

Vishal: What is difference between WAN and Internet?

Me: “Internet” is no different from WAN. But WAN is private, Internet is public and is Inexpensive: no need to invest in corporate network but also Insecure: need to use security software for corporate use.

Vishal: What is the use of using internet?

Me: The advantage is that there is no need for specialist software at each client location. But there is disadvantage attached to it i.e. Business Application has to be “web enabled”.

Vishal: Ok, is it fixed that how to use all the architectures and when to use?

Me:  How to use the architecture depends on the company. As the company run multiple applications e.g.  Payroll, inventory, Human resource etc. they use consolidated multi tier architecture. That is Database, Business applications and Web server can reside on one machine.  It is easy to handle and server management is easy.

Multiple applications have specific requirements and distinct data, Distributed across more than one machine. These applications could be from different vendors or developed in-house, based on different technology platforms such as Oracle/ Excel/ Java / C++.

Vishal: But are they easy to use and handle?

Me: No, there are various complexities generated due to the small databases. The company manage the complexities in two ways

1)      Complexities are generated due to different databases, therefore the company’s rather than having small database they make standard database software called corporate database. Which is managed by management systems called RDBMS

Vishal: What is RDBMS?

Me: it is called Relational database management system, a type of database management system (DBMS) that stores data in the form of related tables

Vishal: Ok

Me: The Advantages of an Integrated Database System are no duplication of data, no inconsistency of data across locations / time periods, easier to manage (Backup and Restore, Security and user access authentication”)

2)      ERP systems (enterprise resource planning)

Enterprise Resource Planning (ERP) systems attempt to integrate all data and processes of an organization into a unified system. A typical ERP system will use multiple components of computer software and hardware to achieve the integration. A key ingredient of most ERP systems is the use of a unified database to store data for the various system modules.

The advantages of an Integrated ERP System are Tighter integration across all functional areas (No separate activity required to synchronise data) and Can be purchase as a single package from established vendors (Benefit from best practices available with other companies, Faster to implement / Easier to manage and maintain)

Vishal:  Ok. Can people like us handle these architectures?

Me:  No, for such kinds of architecture one requires a specialist to handle it. As they have complex architecture and if one require certain specific data they have to pull out from the corporate database server and use it.

Vishal: Is the data secured in such kinds of architecture?

Me: No, the companies have large, complex and distributed systems. For which they connect the application server (Web server, ERP, corporate database) and web browser by WAN. Companies secure the data from hackers by using firewall.

Vishal: Ok

Me: This was in brief about systems architecture. I hope you understood what systems architecture is.

Vishal: Yes Nidhi, thank you so much.

This is the conversation between me and my friend. Who is also studying in B school.

Me: Hi, Vishal how are you doing?

Me: I am fine, what about you?

Vishal: I am not doing well.

Me: Why, any problem?

Vishal: I have to prepare for systems architecture for my exams. But I do not understand it.

Me: Ok. I can help you with the same. I have just attended the lecture.

Vishal: That’s great.

Me: First of all we need to differentiate between Computer science and Information systems engineering. Computer science is partitioned in to two i.e.Data Structures: describes WHAT is to be processed and Algorithms: specifies HOW it is to be processed

 Information Systems is also partitioned into i.e. Data Systems: describes WHAT is to be processed and Application Systems: specifies HOW it is to be processed

Vishal: ok, so the data and applications are the same?

Me: No, One must keep in mind that the Data must be logically distinct from Applications.

Vishal: Ok, there is only one type of architecture?

Me: no, we have different types of application architecture

1)      Single tier:  In this application architecture we are expected to separate the data and applications from each other. Even if they are present on the same physical hardware i.e. laptop / desktop / server.

2)      Two tiers: In this application architecture we separate data and application by separating them physically that is data is on server, which has the different software like Oracle / MySQL / SQL Server / DB2. And different applications are stored on individual machines. There are two  logics of storing in the individual machines one is

a.       Business logic:  those are the business rules

b.      Presentation logic: the GUI : windows, buttons etc

Vishal: What is GUI?

Me: It is Graphic user interface. It is a type of user interface which allows people to interact with a computer and computer-controlled devices. It presents graphical icons, visual indicators or special graphical elements called “widgets”. Often the icons are used in conjunction with text, labels or text navigation to fully represent the information and actions available to a user. But instead of offering only text menus, or requiring typed commands, the actions are usually performed through direct manipulation of the graphical elements. 

Vishal: Ok, go ahead.

Me: yes, the company access the database by using WAN (Wide area network)

Vishal: What is WAN?

Me: It is a computer network that covers a broad area (i.e., any network whose communications links cross metropolitan, regional, or national boundaries.

Vishal:  Is there any advantage of using two tiers instead of single tier.

Me:  There are advantages and disadvantages as well. Advantages are convenient graphics user interface, does not place processing burden on server machine when you have hundreds of users

And the Disadvantages are High Bandwidth requirements: slows down application, Wide Area Network (WAN) issues and Maintenance / Version Control of distributed software.

Vishal: ok, that’s it?

Me: No we have more,

Three tiers: In this application architecture we separate data and application by separating them physically that is data is on server, which has the different software like Oracle / MySQL / SQL Server / DB2.

But in this application is partitioned i.e. Business Logic kept centrally (Changes to business logic done at one location) and Presentation Logic kept locally (Data transfer over network is minimised). They are again accessible by WAN.

Multi tier: This architecture is same as three tier architecture; the difference is that instead of WAN internet is used. It doesn’t require dedicated client but only browser. There is addition of one machine that is called web browser.

Vishal: What is difference between WAN and Internet?

Me: “Internet” is no different from WAN. But WAN is private, Internet is public and is Inexpensive: no need to invest in corporate network but also Insecure: need to use security software for corporate use.

Vishal: What is the use of using internet?

Me: The advantage is that there is no need for specialist software at each client location. But there is disadvantage attached to it i.e. Business Application has to be “web enabled”.

Vishal: ok, is it fixed that how to use all the architectures and when to use?

Me:  How to use the architecture depends on the company. As the company run multiple applications e.g.  Payroll, inventory, Human resource etc. they use consolidated multi tier architecture. That is Database, Business applications and Web server can reside on one machine.  It is easy to handle and server management is easy.

Multiple applications have specific requirements and distinct data, Distributed across more than one machine. These applications could be from different vendors or developed in-house, based on different technology platforms such as Oracle/ Excel/ Java / C++.

Vishal: But are they easy to use and handle?

Me: No, there are various complexities generated due to the small databases. The company manage the complexities in two ways

1)      Complexities are generated due to different databases, therefore the company’s rather than having small database they make standard database software called corporate database. Which is managed by management systems called RDBMS

Vishal: What is RDBMS?

Me: it is called Relational database management systema type of database management system (DBMS) that stores data in the form of related tables

Vishal: ok

Me: The Advantages of an Integrated Database System are no duplication of data, no inconsistency of data across locations / time periods, easier to manage (Backup and Restore, Security and user access authentication”)

2)      ERP systems (enterprise resource planning)

Enterprise Resource Planning (ERP) systems attempt to integrate all data and processes of an organization into a unified system. A typical ERP system will use multiple components of computer software and hardware to achieve the integration. A key ingredient of most ERP systems is the use of a unified database to store data for the various system modules.

There advantages of an Integrated ERP System are Tighter integration across all functional areas (No separate activity required to synchronise data) and Can be purchase as a single package from established vendors (Benefit from best practices available with other companies, Faster to implement / Easier to manage and maintain)

Vishal:  ok, Can people like us handle these architectures?

Me:  No, for such kinds of architecture on requires a specialist to handle it. As they have complex architecture and if one require certain specific data they have to pull out from the corporate database server and use it.

Vishal: Is the data secured in such kinds of architecture?

Me: No, the companies have large, complex and distributed systems. For which they connect the application server (Web server, ERP, corporate database) and web browser by WAN. Companies secure the data from hackers by using firewall.

Vishal: Ok

Me: This was in brief about systems architecture. I hope you understood what systems architecture is.

Vishal: Yes Nidhi, thank you so much.

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