Computer Memory MCQs
High-yield multiple choice questions asked in previous years (UPSC, SSC CGL, JKSSB, RRB & State PSCs).
High-Yield Concept Capsule & Key Facts
📌 Standard computer section across IBPS, SSC CGL Tier 2, JKSSB Junior Assistant, and State exams.
Memory Hierarchy & Primary vs Secondary Storage
- • Memory Hierarchy by Speed & Cost: CPU Registers > Level 1/2/3 Cache > Primary RAM/ROM > Secondary Storage (SSD/HDD) > Tertiary/Offline Media.
- • RAM (Random Access Memory): Volatile primary memory; loses data on power loss. SRAM (Static RAM - uses flip-flops, faster, used in Cache, does not require periodic refreshing) vs DRAM (Dynamic RAM - uses capacitor-transistor pairs, slower, requires continuous dynamic refreshing, used for main system memory).
- • ROM (Read Only Memory): Non-volatile firmware storage storing the BIOS / UEFI bootstrap loader. Types: PROM (Programmable ROM), EPROM (Erasable PROM via UV light), EEPROM (Electrically Erasable PROM - basis of modern flash memory and SSDs).
Storage Units, Virtual Memory & Secondary Media
- • Data Units: 1 Bit (Binary digit 0 or 1) | 1 Nibble = 4 Bits | 1 Byte = 8 Bits | 1 KB = 1024 Bytes | 1 MB = 1024 KB | 1 GB = 1024 MB | 1 TB = 1024 GB | 1 PB = 1024 TB.
- • Virtual Memory: Memory management technique where secondary storage (hard drive/SSD paging file) is utilized as an extension of physical RAM to run programs larger than physical memory.
- • Cache Memory: Ultra-fast buffer memory placed between CPU and RAM to store frequently accessed instructions and reduce memory access latency (Hit ratio).
- • Secondary Media: Magnetic (HDD, magnetic tape), Optical (CD-ROM: 700 MB, DVD: 4.7 GB, Blu-ray: 25-50 GB using blue-violet laser), and Solid State (NAND flash memory, NVMe SSDs).
| Memory Type | Volatility | Speed / Latency | Primary Technology / Usage |
|---|---|---|---|
| CPU Registers | Volatile | Sub-nanosecond (<1 ns) | Holds active operands and program counter |
| Cache Memory | Volatile | 1 - 5 ns | SRAM (L1, L2, L3 cache buffers) |
| RAM (DRAM) | Volatile | 10 - 20 ns | Capacitors + Transistors (Main memory) |
| ROM / EEPROM | Non-Volatile | Moderate | Holds BIOS / UEFI firmware instructions |
| Solid State Drive (SSD) | Non-Volatile | Microseconds | NAND Flash memory; replaces mechanical HDDs |
| Hard Disk Drive (HDD) | Non-Volatile | Milliseconds | Magnetic platters; spinning spindle (RPM) |
Which of the following computer memories is the fastest and placed directly inside the CPU microprocessor architecture?
Why does Dynamic RAM (DRAM) require periodic electrical refreshing cycles?
A group of 4 binary bits is technically termed as a:
Which type of ROM can be erased by exposing the chip window to intense ultraviolet (UV) light?
What is the primary function of Cache Memory positioned between the CPU and main RAM?
Virtual Memory is an operating system illusion that makes use of:
How many Terabytes (TB) are exactly equal to 1 Petabyte (PB) in binary computational units?
Which of the following non-volatile storage technologies has no mechanical moving parts and relies on floating-gate NAND flash memory?
What is the standard data storage capacity of a single-layer, single-sided Digital Versatile Disc (DVD)?
Which basic input/output program needed to boot the computer is permanently stored in ROM or Flash memory on the motherboard?
The process of transferring data blocks from secondary storage to main RAM during virtual memory execution is called:
What happens when a 'page fault' occurs in a computer system?
Which type of memory uses bistable latching circuitry (flip-flops) and is commonly used in high-speed processor Cache?
USB flash drives and modern smartphone internal storage utilize which non-volatile EEPROM memory architecture?
The time required by a magnetic hard disk drive read/write head to move to the targeted concentric track or cylinder is called:
Frequently Asked Questions (Computer Memory)
Q: What is the critical technical difference between SRAM and DRAM?
SRAM (Static RAM) uses bistable latching flip-flops to store each bit; it is significantly faster, consumes less power, but is expensive and used in Cache memory. DRAM (Dynamic RAM) stores bits in capacitors that continually leak charge, requiring periodic electrical refreshing cycles every few milliseconds; it is cheaper, denser, and used as main system memory.
Q: How does Virtual Memory work when physical RAM is exhausted?
Virtual Memory is an operating system mechanism that divides memory into fixed blocks called 'pages'. When physical RAM is filled, the OS swaps idle pages out of RAM into a dedicated section of secondary storage (called a paging file or swap space), freeing RAM for active execution processes.
Q: What storage medium uses a blue-violet laser and what is its standard single-layer capacity?
Blu-ray Disc (BD) uses a shorter wavelength blue-violet laser (405 nm) compared to red lasers in DVDs, enabling tighter data pits and storing 25 GB on a single layer and 50 GB on a dual layer.
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