Out of Order Core

Welcome to out of order, a blog that looks into computer micro-architecture and the micro-architectural vulnerabilities. Over the course of next few posts, we will be taking a dip in the world of Timing Analysis.   Memory Hierarchy Before we look at what timing analysis is, let us take a brief look at memory hierarchy of modern computer system. Alt: A pyramid that depicts memory hierarchy with CPU registers on top followed by L1, L2, and L3 caches, followed by DRAM based memory followed by flash based drives such as Solid State Drive, followed by Hard Disk Drive. The registers and caches reside on CPU and are faster at resolving requests but are very small, the DRAM is larger and plenty fast compared to the Solid State Drive and Hard Disk Drive that takes milliseconds to resolve data. Source (link will open a new tab): https://sites.google.com/site/cachememory2011/memory-hierarchy As e can see the CPU register sits on top and can generally be accessed every clock cycle of the CPU,...