Computer_Composition_Principle

A map of the CPU, registers, memory hierarchy, caches, storage, DMA, and assembly concepts used to understand how software executes on hardware.

A concise introduction to CPUs as instruction-execution engines and the role of registers, pipelines, cores, and the memory hierarchy.

x86-64 register roles: general-purpose registers, stack/frame pointers, RIP, flags, SIMD registers, and ABI-dependent calling conventions.

How DMA lets devices transfer data to and from memory without having the CPU copy each byte, including descriptors, interrupts, and cache/IOMMU considerations.

CPU cache hierarchy, cache lines, MESI-style coherence, store buffers, invalidation handling, memory ordering, and the role of fences.

Main memory as byte-addressable volatile storage, endianness, alignment, locality, and its place between CPU caches and persistent storage.

A qualitative comparison of DRAM, SSDs, and HDDs across latency, throughput, capacity, cost, persistence, and sequential vs. random access.