What is Real-Time?

Real-time is a process when a system provides information to a user at a speed that is almost instant.

Often, online brokerages provide real-time data that showcases stock quotes and respective changes in real-time, with a very non-substantial lag time so as to allow clients to comprehend the investment decisions on the latest and updated information.

Explaining Real-Time

Real-time is one such term that is derived from its usage in early simulation, wherein a real-world process is replicated at a rate that matches the real process, which is now known as real-time simulation.

Most often, analogue computers were competent of simulating faster than real-time, which is again a situation that might be dangerous as a slow simulation if not recognized accurately or accounted for.

While several financial websites offer free stock quotes; most of this data is not real-time and could be a delayed result of almost 20 minutes. Thus, when inspecting stock quotes from any of the financial websites, be cautious of the time that has been posted around the stock quote to evaluate whether the data is real-time or not.

Acquiring precise real-time quotes is vital for trades as even the minor discrepancy in time between the real-time situation and offered quote could turn a profitable situation into a major loss.

Real-Time Computing Criteria

A system is real-time in case the total appropriateness of a specific operation is depending upon logical correctness as well as the time wherein it was performed. Real-time systems and their deadlines can be classified by the results of missing a deadline.

• Hard – missing a deadline is a complete failure of the system.
• Firm – rare deadline misses are bearable but may damage the quality of service of the system. The result’s usefulness is zero after the deadline.
• Soft – the result’s usefulness worsens after the deadline, thus degrading the quality of service of the system.

Therefore, the objective of a hard real-time system is to make sure that all of the deadlines are completed. However, for a soft real-time system, the objective is meeting a few deadlines’ subsets to optimize certain application-specific criteria.

The specific criteria optimized is dependent on the application. But, some examples of the same may include maximizing the number of met deadlines, decreasing the task lateness and increasing the number of priority tasks.