Understanding the Roles of Volatile and Non-Volatile Memory in Modern Devices

Volatile memory is defined by its need for constant power; DRAM stores bits in capacitors that must be refreshed, while SRAM uses latch circuits that are faster but still lose data without power. These technologies provide the main working memory and cache for CPUs. In contrast, non-volatile memory retains data without power, with NAND flash forming the basis of SSDs and other storage media, and NOR flash often holding firmware code that can be executed directly.

The article describes how software loads from non-volatile storage into DRAM, and frequently accessed data is copied into SRAM caches for speed. It also highlights the role of hibernation, where the contents of volatile memory are written to non-volatile storage before power loss, allowing a full restoration later. The piece clarifies that specifications listing separate memory and storage capacities refer to these two different resource types.