6 Computer Memory Free Online FlashCards

What trade-off shapes computer memory systems?

Memory systems balance speed, capacity, and cost: faster storage is usually smaller and more expensive, while larger storage is generally slower.

What does a memory address identify?

An address identifies a storage location where data can be read or written.

What does byte-addressable memory mean?

Each address refers to one byte.

How many locations can an address with $n$ bits identify?

An address with $n$ bits can identify up to $2^n$ locations.

What is a memory word?

A word is the group of bits a processor handles as a unit; it may span several byte addresses.

What does “random access” mean in RAM?

Random access means a location can be accessed directly, without first passing through earlier locations.

What happens to volatile main RAM when power is removed?

Main RAM is commonly volatile: it loses its contents when power is removed. Random access itself does not mean temporary storage.

How do DRAM and SRAM differ in typical use?

DRAM is widely used for main memory because it offers high capacity at relatively low cost; SRAM is faster and commonly used for caches.

What is ROM used for, and what happens to its contents without power?

ROM is non-volatile and retains its contents without power. It commonly stores firmware needed when a system starts, though some ROM technologies can be erased and rewritten.

How does a cache respond to a request for data?

A cache keeps copies of data from a larger, slower memory. If requested data is present, it is a hit; if absent, a miss fetches a block from the next level.

What is temporal locality?

Temporal locality is the tendency for programs to reuse recently accessed data.

What is spatial locality?

Spatial locality is the tendency for programs to access data near recently accessed locations.