The stack holds call frames containing local variables, saved registers, parameters, and return information.
Its allocation and deallocation usually follow function-call nesting.
Correct Answer: C. To store the operating system's management information for a process
Explanation:
A process control block stores state, registers, scheduling data, memory information, and resource references.
The kernel uses it to suspend, resume, and manage the process.
The terminated state indicates that execution has ended and the system is completing cleanup.
The process will no longer be selected for CPU execution.
A process waiting for an event, such as I/O completion, is placed in the waiting or blocked state.
It returns to the ready state after the awaited event occurs.
A process is in the running state while it owns a processor and its instructions are executing.
Only a limited number of processes can be running simultaneously, based on available cores.
Correct Answer: A. A process is a program in execution with state and allocated resources
Explanation:
A program is passive code, while a process is an active execution instance with registers, memory, and resources.
Multiple processes can execute the same program independently.
Correct Answer: D. A controlled trap to a predefined kernel entry point
Explanation:
The system-call instruction triggers a protected transition to a validated kernel handler.
The processor changes privilege level and prevents the application from choosing arbitrary privileged code.
Polling actively reads device status at intervals or in a loop to detect readiness.
Interrupt-driven I/O instead lets the device notify the processor when service is needed.
Correct Answer: B. The process waits until the I/O operation completes
Explanation:
With synchronous I/O, the calling thread does not continue past the request until completion is reported.
Asynchronous I/O allows useful execution to continue while the operation is outstanding.
Direct memory access lets a controller move blocks between a device and memory with minimal CPU involvement.
The CPU is typically interrupted only when the transfer completes or requires attention.