Memory Systems — Practice MCQs for CCAT

Correct Answer: D — Register

Hierarchy: Registers > Cache > RAM > SSD/HDD.

Correct Answer: A — Between CPU and RAM

Cache is between CPU and main memory for faster access.

Correct Answer: B — Data found in cache

Cache hit: requested data is found in cache.

Correct Answer: B — Locality of reference

Cache exploits temporal and spatial locality of reference.

Correct Answer: A — Block can go anywhere

Fully associative: any block can be in any cache line.

Correct Answer: B — Block has one fixed location

Direct mapped: each block has exactly one possible cache location.

Correct Answer: B — Writes to cache and memory simultaneously

Write-through updates both cache and main memory on every write.

Correct Answer: B — Writes to cache, updates memory later

Write-back: writes to cache, updates memory only when evicted.

Correct Answer: C — SRAM is faster, no refresh needed

SRAM is faster and doesn't need refresh; used for cache. DRAM needs refresh.

Correct Answer: B — Non-volatile

ROM (Read Only Memory) is non-volatile - retains data without power.

Correct Answer: C — Registers

Registers are located within the CPU and have the fastest access time, typically less than 1 nanosecond.

Correct Answer: B — Programs tend to access the same or nearby memory locations repeatedly

Locality principle states that programs tend to access the same data (temporal locality) or nearby data (spatial locality) repeatedly.

Correct Answer: B — DRAM

DRAM (Dynamic RAM) stores data in capacitors that leak charge, requiring periodic refresh to maintain data.

Correct Answer: B — Translate virtual addresses to physical addresses

The MMU translates virtual addresses used by programs to physical addresses in actual memory.

Correct Answer: B — In one specific cache line only

In direct-mapped cache, each memory block can only go to one specific cache line determined by its address.

Correct Answer: B — Least Recently Used

LRU (Least Recently Used) replaces the cache block that has not been accessed for the longest time.

Correct Answer: B — Using hard disk space as an extension of RAM

Virtual memory uses secondary storage (hard disk) to extend the apparent size of physical RAM.

Correct Answer: B — Required page is not in physical memory

A page fault occurs when a program accesses a page that is not currently in physical memory, requiring it to be loaded from disk.

Correct Answer: B — Registers > Cache > RAM > Hard Disk

The memory hierarchy from fastest to slowest is: Registers > Cache > RAM > Hard Disk/SSD.

Correct Answer: B — Indicates the cache line has been modified and differs from main memory

The dirty bit indicates that the cache line has been modified (written to) and needs to be written back to main memory before replacement.

Correct Answer: C — Combination of direct and associative - cache divided into sets

Set-associative cache divides cache into sets, where a block maps to a specific set but can go in any line within that set.

Correct Answer: B — Time taken to load data from main memory on a miss

Cache miss penalty is the additional time required to fetch data from main memory when data is not found in cache.

Correct Answer: B — Electrically Erasable Programmable ROM

EEPROM is Electrically Erasable Programmable ROM - can be erased and reprogrammed using electrical signals.

Correct Answer: B — Recently accessed data is likely to be accessed again soon

Temporal locality means that data that has been recently accessed is likely to be accessed again in the near future.

Correct Answer: B — Data near recently accessed locations is likely to be accessed soon

Spatial locality means that if a memory location is accessed, nearby memory locations are likely to be accessed soon.