Which mechanism does an operating system use to allocate CPU time among multiple tasks?

Which mechanism does an operating system use to allocate CPU time among multiple tasks?

• A. BIOS
• B. Network stack
• C. File system
• D. Scheduler

Answer: (D)

The mechanism used by an operating system to allocate CPU time among multiple tasks is the scheduler. The scheduler decides which task runs next, when it should run, and for how long. It relies on timing information from the system clock and performs context switches to save the state of the current task and load the state of the next one. This enables true multitasking, letting interactive programs stay responsive while background tasks progress, often using policies like fairness, priority, or round-robin and sometimes preemption to enforce limits on any single task’s run time. Other components mentioned don’t handle CPU-time allocation: the BIOS is firmware that runs during boot to initialize hardware, not to manage ongoing task scheduling; the network stack handles data transmission over networks; the file system manages reading and writing persistent storage.

The mechanism used by an operating system to allocate CPU time among multiple tasks is the scheduler. The scheduler decides which task runs next, when it should run, and for how long. It relies on timing information from the system clock and performs context switches to save the state of the current task and load the state of the next one. This enables true multitasking, letting interactive programs stay responsive while background tasks progress, often using policies like fairness, priority, or round-robin and sometimes preemption to enforce limits on any single task’s run time.

Other components mentioned don’t handle CPU-time allocation: the BIOS is firmware that runs during boot to initialize hardware, not to manage ongoing task scheduling; the network stack handles data transmission over networks; the file system manages reading and writing persistent storage.