Operating System MCQs

Layering organizes the system into levels with controlled interfaces between adjacent or lower layers.
The structure improves modular reasoning but can introduce design and performance constraints.

A microkernel minimizes privileged code and implements many services as user-space servers.
Those servers communicate through message passing rather than direct in-kernel procedure calls.

A modular kernel allows separately developed components to be loaded and linked into kernel space as needed.
It combines extensibility with direct in-kernel performance.

A hybrid kernel adopts modular or microkernel concepts while retaining substantial kernel-space functionality.
The goal is to balance performance, compatibility, and modularity.

The interrupt vector provides the processor with the correct handler location for each interrupt type.
It avoids searching through all handlers whenever an interrupt occurs.

open() validates access and returns a file descriptor or equivalent handle for later operations.
Reading and writing then refer to that handle rather than repeatedly resolving the pathname.

ioctl() conveys device-specific control commands that do not fit ordinary read or write operations.
It is therefore classified as a device-management interface.

Queries such as obtaining a process ID, time, or system data are information-maintenance calls.
They retrieve or update system and process attributes rather than manipulate files or memory pages.

A monolithic kernel runs many operating-system services together in privileged kernel space.
This can provide fast communication but increases the amount of code that shares kernel privileges.

A command-line interface accepts textual commands entered through a shell or command interpreter.
A graphical interface relies mainly on windows, icons, menus, and pointing actions.

A graphical user interface presents visual controls that users manipulate directly.
The other choices describe internal operating-system mechanisms rather than a user interface.

A system call is the programmed entry point through which user software requests a kernel service.
The transition is controlled so privileged operations remain protected.