Final answer:
Operations that must execute within specified deadlines are characteristic of Hard real-time systems, which cannot tolerate delays without risking system failure.
Step-by-step explanation:
The operations that must execute within specified deadlines are a characteristic of Hard real-time systems. These systems are designed to perform their tasks within a strict time constraint, and missing a deadline could lead to catastrophic outcomes.
In contrast, Soft real-time systems prioritize completing tasks on time, but they can tolerate some delays without causing a system failure. In-house real-time systems and Build-in real-time systems are not commonly used terms in the context of real-time computing.