systems engineer · rust · c · solana
Valentyn Kit
Six years building distributed systems and platforms. Right now: the Rust core of a money-movement platform — durable state machines, multi-chain signing, exactly-once semantics. Nights and weekends I go one level deeper, rebuilding the foundations from scratch: databases, TCP servers, a key-value store in C. To understand, not just use. This blog is the log: what holds in production, and what you find rebuilding the foundations yourself.
writing
- What Linux actually does when you read a file
I asked for one 4 KiB page and got four back. The same read one page over gave me one.
- You don't understand a system until you've rebuilt it
Using a system teaches its interface and reading its source teaches its mechanics, but only rebuilding a worse version teaches the constraints, which is where understanding actually lives. Why reconstruction works, and how to build a toy that teaches you something instead of lying to you.
- Rust's compile errors are other languages' production bugs
Four Rust compiler refusals, each traced to the silent bug it prevents in Python, JavaScript, or C: float sorting, string indexing, integer overflow, lazy iterators. Plus the one place Rust stays quiet.
- From one blocking accept() to epoll: a C TCP server up the I/O ladder, measured
Building a TCP echo server in C seven times, from blocking through select, poll, kqueue, and epoll, with the cost of each wall measured: a 1.5 second stall, a pegged core, the FD_SETSIZE ceiling, and O(ready) dispatch.
- Framework knowledge evaporates. Low-level knowledge compounds.
I learned async three times before it clicked. Building a TCP echo server from blocking sockets up through kqueue and epoll in C, seven times, is what finally fixed it.