Operating System MCQs

A process identifier, or PID, is used by the kernel and programs to refer to a specific process.
The other values identify memory positions, file types, or disk locations rather than processes.

A ready process is prepared to execute and is waiting only for processor time.
A blocked process waits for an event such as I/O completion instead.

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.

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.

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 control block stores state, registers, scheduling data, memory information, and resource references.
The kernel uses it to suspend, resume, and manage the process.

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.

The new state represents a process that is being created and initialized.
After admission, it normally enters the ready state.

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.

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.

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.

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.