You will find many instance where users ask for real time in the requirements. Such requirements must always be check carefully for many reasons. This is because real time design is costly. How do you determine the need of real time? These are some standard queries you can ask before you embark on real time design.
A common way to check for real time is the type of system you will be designing. Mission critical system like a car application will need real time design because your car requires instant feedback on the road. Another such system is airline control tower where you will be managing incoming and outgoing aircrafts. Such systems will need a real time infrastructure compared to standard applications. The design is usually highly availability, resilient and fault tolerance.
I want Real Time for Free
The challenges come when your users want real time data refresh in your system. The correct term that you need to use is “near real time”. This means you can achieve data refresh with a tolerance lag of five minutes or more. Another term is “live streaming” where you may design a dedicated pipeline for data refresh. Such design will incur higher cost and must be segregated for your premier customers. In another words, real time requirements should be segmented properly in your product offerings with a cost.
Real time requirements will impact your design and cost greatly. Mission critical systems are real time from backbone to front end. For other applications, real time could be a specific feature. You must always take note that the cost of implementation for real time is always higher than standard requirements. Thus, you must consider these additional cost when you market your products.