This is the cumulative result of my coursework for the Computer Systems Fundamentals (CSF) course at Johns Hopkins University. This course covers the design and performance of computer systems, ranging from simple 8-bit microcontrollers to 32/64-bit RISC and x86 CISC architectures. It starts with logic gates and digital circuits, progressing to topics like arithmetic and logic units, registers, caches, memory, and pipelined execution. The course also includes instruction set architectures, interrupts, and peripheral communication protocols, with practical programming projects in assembly language and processor simulators.