Amazon.com is an online retail store that offers product lines

include books, music CDs$,$ video tapes and DVDs$,$ software,

are much more. Amazon handles millions of back$-$end

operations every day, as well as queries from more than half

a million third$-$party sellers. $[3$ marks$]$

ii$)$ Dropbox is a file hosting service operated by Dropbox, Inc.

that offers cloud storage, file synchronization, and client

software. In brief, Dropbox allows users to create a special

folder on each of their computers, which Dropbox then

synchronizes so that it appears to be the same folder $($with

the same contents$)$ regardless of the computer it is viewed

on$.$ Files placed in this folder are also accessible through a

web site and mobile phone applications. $[3$ marks$]$

iii$)$ Suppose that you are to design a Gmail like mail system. The

incoming mails are scanned for different security checks at

different level one after other. Each level has its own

functionality and depends on input from previous levels. For

designing such system, what is the best possible architecture

that can be used for this situation. $[3$ marks$]$

iv$)$ If you have to design a system that reads a set of student

marks for the last $10$ years from a file, on which you need to

select fall semester marks, then you need to group these

marks based on various subjects, sort these records based on

marks, and finally report the sorted marks and a statistical

trend analysis $($mean$,$ median, etc.$).$ Which architectural

style would you prefer. $[3$ marks$]$