This is a conversation between Pallav a Mechanical Engg. Working in a well recognised automobile firm and me. The dialogue is on system architecture. Its starts with my explanation on system architecture.
“System architecture is the design or set of relations between the different parts of a system or in other words it is mapping between the functionality of hardware onto software or vice versa and to human interaction with these components. In this data and application is distinct. Data is not embedded in application.”
Then the dialogue follows
P: Can you tell me the different types with their advantages over other?
M: There are four typesSingle tierData and application are on the same system and needs to be separatedIts advantage isLess data travel. So faster processing.Its disadvantage is Duplication is high. Updating of data needs to be done on every system.
Two tier
Here data and applications are separated. Data is stored in servers and application resides on each system. Here all systems and data server are integrated through a common network. Its advantages areConvenient graphic user interfaceProcessing burden is in individual machines only data flow occurs. Therefore server is not burdened.Its disadvantages are as data transfer is required high bandwidth is needed.WAN and maintenance is an issue.
Three tier
Data and application separated but business application is at the server side and presentation application at the user side. This reduces data travel. Server and systems connected through common network. Specialist software needed at each end to talk.changes in application needed to be done at one end only.
Multi tier
Server side is divided into three data server, application server, web server as the machines are integrated through internet. Here all the three servers can me merged in one big machine or can have combination on 2 and one machine.AdvantagesCheap networkNo need for special software at each end to talk
Disadvantages are attack prone as internet most unsecured one.Business application has to be web enabled.
P: Which on is best?
M: It is according to the firm’s strategy and surely single tier isn’t good.Two tier system can have specific applications such as sales, finance HR. These applications are on the user machines and the data in the partitioned server. These applications are platform independent i.e. any vendor or any language.it is decided as per the advantages offered and advantages desired.
P: How complexity can be managed?
M:Today to manage complexity an integrated database is used (RDBMS).this is done to ensure no redundancy, seamless flow of data, easy backup and finally secure to have integrated database.Another way to reduce complexity is to use modules and integrated database so that client needs only software i.e. implement ERP. In addition special requirements can be handled by having special server with database in line with main. But with lower speed as it will not be used often. In large and complex distributed system in which end users are integrated to servers through WAN basically server is divided into 3 parts web server, application and data server.
P: How to secure the network?
M: For security reasons from hackers firewalls are needed on both sides of connection although it slows down the data flow.Development of application system depends on the platform being used for relational model and development. Basically ZOHO is used on the both fronts.
Finally his questions stopped as he was satisfied with the answers he got and also his queries were over.He conceived it to be a useful dialogue.
