Real time is a guaranteed level of computer responsiveness within a specified time constraint, usually milliseconds or microseconds, between an event and its response deadline. Real time describes a human sense of time (rather than machine time) that seems immediate. For example, real-time weather maps appear to portray immediate changes, when actually several milliseconds may have elapsed between image updates. In contrast to mainframe batch computers, where processes are grouped and scheduled for processing at later times, real-time computer processes occur without delay. In computer simulations, “real time” means the simulation’s clock runs at the same speed as an actual clock, not in fast-motion or slow-motion.
Real-time computing (RTC), also known as reactive computing, describes hardware and software systems guaranteed to respond within a given timeframe. Real-time software applications often require synchronous programming languages, real-time operating systems and real-time networks to execute processes by the specified deadline, regardless of system load. Examples of real-time software include aircraft navigation programs, multimedia broadcasts, multi-player video games, data analysis programs and stock-trading applications.
The success of many large enterprises depends on the real-time responsiveness of their IT systems. If a business can respond quicker to new information and changing market conditions, it gains an advantage over businesses that cannot. Running time-sensitive applications in real time reduces process delays (latencies), offering an advantage over competitors. Reduced latency, combined with virtualization, maximizes application performance. Operating systems with a pre-emptible real time kernel can provide precise timing and synchronization for advanced application workloads. SUSE Linux Enterprise Real Time is an open source, real time operating system designed to reduce latency and increase the predictability and reliability of time-sensitive and mission-critical applications.