Understanding Computer Memory Architecture and SSD Internals

[](http://codingpirate.com/?source=post_page---byline--ac9320110787-----------------------------------------) 39 min read 2 days ago Press enter or click to view image in full size  Memory is a hardware component that stores binary information in blocks. Every memory device stores data as a sequence of binary digits (1s and 0s). Memory often appears as one continuous address space, but physical computer systems are built from multiple memory technologies arranged in a hierarchy. Each technology has its own form factor and involves trade-offs among capacity,_access latency, bandwidth, power consumption_, and _manufacturing cost_. Memory elements retain information over time, allowing digital systems to preserve state and execute sequential operations. Every piece of information processed inside a computer eventually resides in some form of memory. Program instructions, variables, images, cryptographic keys, network packets, and intermediate computation results are all represented as binary values stored within a memory device. ## Common Characteristics of Memory Zero access latency Non-volatile data retention Low power consumption Unlimited storage capacity ## Memory Structure A memory is represented as a large rectangular area with width and depth. The width represents the number of bits that can be allocated to a single memory block index, and depth defines the number of data-block locations. > For example: If a data-bit is 8-bit wide and stored in 128 locations, then the total memory bits are 128 x 8 = 1024 bits. Press enter or click to view image in full size  Memory capacity is determined by WIDTH x DEPTH  ## Memory Operations Every memory device supports two fundamental operations Read: retrieves the data stored at a specified memory address. Write: stores new data at a specified memory address. ### Common memory interfaces Address Bus Data Bus Read Enable Write Enable Clock (for synchronous memories)  ## Memory Hierarchy In the previous section, I have described memory as a rectangular storage structure organized by its width and depth. This representation is useful for understanding how data is stored but it does not accurately describe how memory is organized within a modern computer system. A _general-purpose_ computer does not contain a single memory device. Instead, it consists of multiple memory technologies, each designed to satisfy different requirements for _performance_, _capacity_, _access latency_, and _manufacturing cost_. These memory technologies are organized into a memory hierarchy, where each level balances storage capacity and access speed differently. Press enter or click to view image in full size  When a processor executes a program, it continuously requests instructions and data from memory. The processor first checks the smallest, fastest memory closest to the execution units rather than accessing main memory directly. If the requested