A real-time system can respond to events with no significant time lag. This is primarily an IT term, but it is often used in the context of financial data and banking and trading systems.
- Real-time data is data that is supplied with no significant delay.
- Real-time settlement takes place as trades occur.
Given the value of financial data and the importance of timeliness users can usually expect the pricing of access to data to reflect the time taken to deliver it.
For example, one can get share prices with a delay (usually of around 20 minutes) free. Getting access to real time share prices will require a fee. The vendors can thus make more money out of the people who really need the real time numbers.
In IT, the opposite of a real time system is a batch processing system which collects data over a period of time and processes it together. Settlement that takes place at fixed times (typically at the end of the trading day) are an example of batch processing.
Batch processing systems usually make more efficient use of computers. They have therefore become less common as computing power has become cheaper. Batch processing is now used only for very large complex processing, or where it reflects the actual requirement.
The term hard real time is used to describe systems in which failure to respond within a particular (very short) time is a critical failure (e.g. a car's braking system). Adding real time or hard real time capabilities to software may expand its potential market.