CS-Base

CS-Base is a Chinese-language study site that explains foundational topics of computer science — computer networks, operating systems, computer organization, and databases — using illustrated, plain-language articles. The author, who writes under the handle Xiaolin Coding, originally published these on a WeChat public account, then collected them on a dedicated website. The pitch is roughly: about a thousand diagrams and half a million words aimed at making dry CS basics approachable, so interview-style fundamentals stop feeling like impenetrable jargon.

It is not software you run; the repository is essentially the source and an index of links into the published book at xiaolincoding.com. Each chapter is broken into short, focused articles. The networking section walks through the TCP/IP model, what happens when you type a URL into a browser, HTTP versions one through three, HTTPS handshakes, TCP's three-way handshake and four-way teardown, retransmission, sliding windows, congestion control, and many TCP edge cases drawn from real interview questions. The operating systems section covers CPUs, caches, memory and virtual memory, processes and threads, scheduling, file systems, devices, the high-performance networking patterns Reactor and Proactor, and I/O multiplexing with select, poll, and epoll. There is also a section on MySQL covering indexes, row storage, and B+ trees.

People reach for it when preparing for backend or systems interviews, refreshing fundamentals, or trying to understand why something low-level behaves the way it does, in a more visual style than a textbook. Topics tagged on the repo include C, C++, Go, Java, Python, Linux, network, and TCP.