CPU, Memory & Storage Devices MCQs with Answers — 60+ Solved (2026)
Solved CPU, Memory & Storage Devices MCQs with answers — ALU, RAM, ROM, Cache, HDD, SSD, Flash Drive. Free quiz + PDF for PPSC, FPSC, NTS, CSS & PMS.
CPU, Memory & Storage Devices — Master Reference for Pakistani Competitive Exams
The chapter CPU, Memory & Storage Devices is the highest-weightage Computer Science topic 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 3–5 MCQs from this single chapter. This page consolidates 60+ solved MCQs with answers covering the CPU’s three parts (Memory Unit, Control Unit, ALU), all main memory types (RAM, ROM, Cache, Buffer), key concepts (LRU, FIFO, Cache HIT, Snoopy Writes, Access Time) and every common storage device (HDD, SSD, Flash Drive / Pen Drive, CD/DVD, Disk Array, Stripping, Bernoulli Disks).
CPU — The Three Parts
| Part | Full Name | Function |
|---|---|---|
| 1st — MU | Memory Unit | Stores instructions, data and intermediate results. |
| 2nd — CU | Control Unit | Controls the operation of all parts of the computer. Does NOT carry out actual data processing. |
| 3rd — ALU | Arithmetic Logic Unit | Digital circuit that performs arithmetic and logic operations. |
RAM vs ROM — Quick Comparison
| Feature | RAM | ROM |
|---|---|---|
| Full Form | Random-Access Memory | Read Only Memory |
| Volatility | Volatile — data lost when power off | Non-Volatile — data retained |
| Read/Write | Read & Write | Read only — cannot write |
| Contents | Can be changed | Cannot be altered |
| Purpose | Stores data, programme & results currently in use | Permanent / firmware storage |
Storage Devices — Types & Characteristics
| Device | Type | Volatile? | Key Fact |
|---|---|---|---|
| HDD | Magnetic | Non-Volatile | Large capacity, spinning platters |
| SSD | Solid State | Non-Volatile | Faster than HDD, no moving parts |
| RAM | Electronic | Volatile | Primary memory, directly CPU-accessible |
| ROM | Electronic | Non-Volatile | Read only, contents cannot be altered |
| CD / DVD | Optical | Non-Volatile | Uses laser light to read/write data |
| Flash Drive | Flash (NAND) | Non-Volatile | Also called Pen Drive — portable storage |
| Cache | SRAM | Volatile | High-speed; speeds up the CPU |
Key Facts to Memorise
- CPU — Brain of the computer; performs all data processing and controls all parts.
- 3 Parts of CPU — Memory Unit · Control Unit · Arithmetic Logic Unit (ALU).
- ALU — Digital circuit that performs arithmetic and logic operations.
- Control Unit — Controls all parts but does NOT carry out actual data processing.
- Programme Counter — CPU fetches instruction from memory based on its value.
- Logical Address — The address generated by the CPU.
- Two major chips — Primary memory chip and microprocessor chip.
- Two types of main memory — RAM and ROM.
- RAM — Volatile, read/write, primary memory.
- ROM — Non-volatile, read only, contents cannot be altered.
- Cache memory — Very high-speed semiconductor memory implemented using SRAM chips.
- Cache HIT — When data is found in the cache memory.
- LRU — Least Recently Used; cache replacement policy.
- FIFO — First In First Out; page replacement algorithm.
- Snoopy Writes — Efficient method for updating the cache.
- Buffer — Temporary storage place for information.
- Access Time — Time required to locate and transfer data.
- Chip — Extremely small piece of silicon on which integrated circuits are fabricated.
- HDD — Hard Disk Drive; non-volatile magnetic storage.
- SSD — Solid State Drive; non-volatile, no moving parts.
- Flash Drive / Pen Drive — Uses NAND flash memory; portable.
- Optical Storage — CD, DVD and Blu-ray.
- Disk Array — Multiple HDDs with a controller in a single box.
- Stripping — File partitioned into smaller parts and stored across different disks.
- Bernoulli Disks — A type of magnetic hard disk.
- Winchester Disk — NOT an optical disk (it is magnetic).
Exam tip: Lock six anchors and you cover ~80% of all MCQs from this chapter — 3 parts of CPU (MU/CU/ALU), RAM = volatile / ROM = non-volatile, Cache = SRAM, high speed, LRU vs FIFO, HDD vs SSD, and Flash Drive = Pen Drive (NAND).
Frequently Asked Questions
The CPU has three parts: (1) Memory Unit — stores instructions, data and intermediate results; (2) Control Unit — controls the operation of all parts of the computer (does NOT do actual data processing); and (3) ALU (Arithmetic Logic Unit) — a digital circuit that performs arithmetic and logic operations.
RAM (Random-Access Memory) is volatile read/write memory that loses its contents when the power is switched off. ROM (Read Only Memory) is non-volatile and can only be read from — its contents cannot be altered.
Cache memory is a very high-speed semiconductor memory implemented using SRAM chips. It speeds up the CPU by storing the most frequently accessed data and instructions, reducing the time the CPU spends waiting on slower main memory.
LRU (Least Recently Used) is a cache replacement policy — it discards the data that hasn’t been used for the longest time. FIFO (First In First Out) is a page replacement algorithm — it replaces the oldest entry first.
HDD (Hard Disk Drive) is a non-volatile magnetic storage device with spinning platters. SSD (Solid State Drive) is a non-volatile storage device with no moving parts — it is faster, more shock-resistant and consumes less power than an HDD.
A flash drive — commonly called a pen drive — is a non-volatile solid-state storage device that uses NAND flash memory (made of millions of transistors). It enables easy transport of data from one computer to another.
Yes — essential. CPU, memory and storage devices are tested in every One Paper, NTS NAT, GAT, OTS, CTS, BPSC, KPPSC, SPSC, PPSC and FPSC exam. Expect 3–5 MCQs from this chapter in any 100-mark paper.
Yes. Click the Download PDF button in the hero or quiz section to get all 60+ CPU, Memory & Storage Devices MCQs with correct answers as a branded QuizWing PDF for offline revision.