what are real-time captions for the deaf?

Real time typed conversation on a computer is known as a chat.

Yes, real-time operating system is the type of operating system most people use on their desktop and laptop computers today. For a real-time OS, programs are executed the instant they are sent to the CPU without batching or queuing.

Audio / video editing

digital signal processing

gaming

encryption / decryption

compression

sensors eg: light sensors on smart phones

When there is lettle time or no time to plan. Often used during the execution phase of an operation where an unplanned change occurs and must be managed. It's easily applied to on- and off-duty situations.