Computer Science Knowledge Base

A structured, top-down path through how computers actually work: from a single instruction executing on a CPU, up through memory, storage, and the operating system, out to networks and the databases built on top of all of it. Pages favor why the layer exists and what breaks when you ignore it over trivia — grade-school basics (binary counting, "what is a computer") are skipped or covered in one line.

How this is organised

Bottom-up on hardware (CPU → Memory → Storage → Buses), then up through the Operating System that multiplexes that hardware, then out to Networks, Protocols, and Databases — the systems built using everything below them. See the Overview page for the full reasoning.

Sections

	Section	What it covers
	Overview	The abstraction-layer mental model and reading order
	Data Representation	Binary/hex, two's complement, bitwise techniques
	CPU & Processor Architecture	ISA, fetch-decode-execute, pipelining, superscalar/OoO, multicore
	Memory Hierarchy & RAM	Registers, caches, DRAM, virtual memory
	Storage: HDD, SSD & NVMe	Magnetic disks, NAND flash, storage interfaces
	Buses & I/O	Address/data/control buses, PCIe, DMA, interrupts
	Operating Systems	Processes/threads, scheduling, memory management, sync
	Assembly & Low-Level Programming	Registers, instructions, calling conventions, disassembly
	Computer Networks	OSI/TCP-IP models, data link, IP, TCP/UDP
	Application Protocols	DNS, HTTP/HTTPS, TLS
	Databases	Relational model, indexing, ACID, NoSQL/CAP
	Algorithms & Data Structures	Complexity analysis, core data structures, sorting, searching, graph algorithms, problem-solving patterns

Suggested Reading Path

• New to systems programming: Overview → CPU & Processor Architecture → Memory Hierarchy & RAM → Operating Systems.
• Backend / infrastructure focus: Operating Systems → Computer Networks → Application Protocols → Databases.
• Performance engineering: CPU & Processor Architecture (all pages) → Memory Hierarchy & RAM → Assembly & Low-Level Programming.

Conventions used across these docs

• Figures (real diagrams and photographs) are used wherever one exists for the concept; Mermaid is reserved for flows and decisions that no static figure captures well. Every figure carries a caption and its source — the full list lives in static/img/cs/SOURCES.md.
• Tables are preferred over prose for comparisons.
• Admonitions flag the important bits: info for context, warning/danger for real foot-guns (security issues, performance traps).
• Every page ends with a References section and a Books & Videos subsection pointing at the specific chapters, official specs, or videos worth going deeper on — this KB is meant as a map, not a replacement for the primary sources it cites.