Operating System MCQs with Answers
Solved Operating System MCQs with answers — Linux, UNIX, kernel, system calls, deadlock, PCB & throughput. Free quiz + PDF for PPSC, FPSC, NTS, CSS & PMS.
Operating System — Master Reference for Pakistani Competitive Exams
The chapter Operating System is one of the most repeated Computer Science topics in Pakistan’s PPSC, FPSC, NTS, CSS, PMS, OTS, CTS, BPSC, KPPSC and SPSC One Paper exams. Every Junior Clerk, Assistant, Sub-Inspector, Lecturer and BPS-14 to BPS-17 paper carries 2–4 MCQs from this chapter. This page consolidates solved MCQs with answers covering OS basics (Linux, UNIX, OS X), the three kernel types (monolithic, microkernel, hybrid), all six OS management functions (memory, device, job accounting, system performance, CPU deallocation, system calls), complete process management (PCB, process states, deadlock, programme counter) and the most-asked terms — throughput, multiprogramming, DTrace, command interpreter, log file.
OS Layer Structure
Top to bottom: User → Application → Operating System → Hardware. The OS sits between the application layer and hardware, exposing services through System Calls.
Six OS Management Functions
| Function | Description |
|---|---|
| Memory Management | Keeps track of the primary memory. |
| Device Management (I/O Controller) | Keeps track of all devices; decides which process gets the device, when, and for how long. |
| Job Accounting | Keeps track of time and resources used by various jobs and/or users. |
| Control over System Performance | Records delays between the request for a service and the response from the system. |
| CPU Deallocation | Helps deallocate the CPU when the processor is no longer required for process execution. |
| System Calls | Provides an interface to access services of the Operating System. |
Three Types of Kernels
| Kernel Type | Description |
|---|---|
| Monolithic Kernel | All OS services run in kernel space. Fast but large. |
| Microkernel | Only essential services in kernel space; the rest run in user space. More modular. |
| Hybrid Kernel | A combination of two different kernel types. Used in OS X. |
Key Facts to Memorise
- OS — Set of programmes that controls, supervises and supports hardware and application packages.
- Layer order — User → Application → Operating System → Hardware.
- Oracle is NOT an operating system (it is a database).
- Linux — An open-source operating system.
- Unix-based systems — Offer both Command Line Interface (CLI) and Graphical User Interface (GUI).
- OS X — Uses a hybrid kernel.
- Hybrid kernel — A combination of two different kernels.
- System calls — Provide the interface to access OS services.
- Command interpreter — Main function is to get and execute the next user-specified command.
- Process failure — Most operating systems write the error information to a log file.
- DTrace — A facility that dynamically adds probes to a running system, both in user processes and the kernel.
- Multiprogramming systems — Allow more than one process execution at a time.
- Throughput — Number of processes completed per unit time.
- Blocked state — Process is unable to run until some task has been completed.
- Running state — Process is using the CPU.
- Process Control Block (PCB) — Does NOT contain a bootstrap programme.
- Process stack — Does NOT contain the PID of a child process.
- Programme Counter — Provides the address of the next instruction to be executed by the current process.
- Deadlock — A set of processes is in deadlock if each process is blocked and will remain so forever.
Exam tip: Lock six anchors and you cover ~80% of all MCQs from this chapter — Linux = open source, OS X = hybrid kernel, 3 kernel types (monolithic, microkernel, hybrid), System Calls = OS interface, Throughput = processes/unit time, and Deadlock = all processes blocked forever.
Frequently Asked Questions
An Operating System (OS) is a set of programmes that controls, supervises and supports a computer system’s hardware and application packages. The standard OS layer order is User → Application → Operating System → Hardware.
Linux is an operating system of open source. Unix-based systems offer both a command line interface (CLI) and a graphical user interface (GUI).
A hybrid kernel is a combination of two different kernels — typically combining elements of monolithic and microkernel designs. OS X uses a hybrid kernel.
A set of processes is in deadlock if each process is blocked and will remain so forever — none can proceed because each is waiting for a resource held by another.
Throughput is the number of processes completed per unit time. It is one of the key performance metrics used to evaluate an operating system.
A Process Control Block (PCB) is a data structure used by the OS to store information about a process — including its state, program counter, registers, scheduling info and memory limits. It does NOT contain a bootstrap programme.
Yes — essential. Operating Systems are tested in every One Paper, NTS NAT, GAT, OTS, CTS, BPSC, KPPSC, SPSC, PPSC and FPSC exam. Expect 2–4 MCQs from this chapter in any 100-mark paper.
Yes. Click the Download PDF button to get all Operating System MCQs with correct answers as a branded QuizWing PDF for offline revision.