The relationship between Registers, Main Memory, and Disk Storage defines the crucial performance/capacity trade-offs within a computer system, each element occupying a distinct tier in the memory hierarchy. Registers represent the fastest tier, built from highly expensive SRAM and located directly within the CPU core. They have the lowest latency, accessing data within a single clock cycle, but possess the smallest capacity, typically holding only dozens of bytes of data necessary for immediate instruction processing. Both registers and Main Memory are volatile, meaning their data is lost when power is removed. Main Memory (DRAM) occupies the intermediate tier, offering much larger capacity (gigabytes) at significantly higher latency (hundreds of clock cycles) than registers. It holds the active code and data for running applications. At the bottom is Secondary Storage (Disk, either magnetic HDD or flash-based SSD). This tier offers the largest capacity (terabytes) at the lowest cost per byte, but suffers from the highest latency, with access times measured in milliseconds. Its defining characteristic is non-volatility; it provides the persistent, archival storage required for the long-term retention of files and operating system data, ensuring the system can be restored after a power loss. The efficient performance of the entire computer rests on the OS’s ability to constantly shuffle data up and down this spectrum based on the CPU’s immediate needs.