CPU sharing model: Which technique switches jobs so rapidly that each appears to have the computer to itself, thereby sharing processor time among several jobs?

Introduction / Context:
Modern operating systems give the illusion that multiple applications run simultaneously on a single CPU by rapidly interleaving execution. This foundational concept underlies interactive computing and multi-user systems. The question asks for the name of this technique.

Given Data / Assumptions:

• A single processor serves multiple jobs or users.
• Jobs are switched frequently in very small time slices.
• Users perceive responsiveness as if they had dedicated hardware.

Concept / Approach:

Time sharing divides CPU time into quanta (time slices). A scheduler allocates these quanta among runnable processes. Rapid context switching plus preemption creates an interactive illusion even with limited hardware. This is distinct from simple batch processing or first-in, first-out queues without preemption.

Step-by-Step Solution:

Verification / Alternative check:

Historical systems (e.g., early Unix on minicomputers) exemplify time-sharing, providing terminals with responsive sessions via preemptive scheduling and quanta.

Why Other Options Are Wrong:

• time out: Refers to an expiration event, not CPU sharing.
• time domain: A signal-processing phrase, not a scheduling model.
• FIFO: A queue discipline; without preemption, it does not ensure interactive responsiveness.
• None of the above: Incorrect because time sharing is the established term.

Common Pitfalls:

Confusing cooperative multitasking (non-preemptive) with time sharing; assuming FIFO alone yields interactivity; ignoring the role of time quanta and preemption.

Final Answer:

time sharing