Virtual Threads Are Not Async I/O: Lessons from Operating System Archaeology, Ivan Yonkov

This talk explores the origins of asynchronous programming, tracing its roots back to the early days of Java and the concepts of OVERLAPPED I/O and I/O Completion Ports (IOCP). The speaker examines how asynchronous I/O was implemented at the operating system level long before the advent of features like reactive streams and CompletableFuture. By uncovering the fundamental mechanics that still influence modern Java applications, the session aims to provide clarity on how the JVM operates under the hood, enabling developers to make more informed architectural decisions and effectively debug asynchronous issues. This discussion emphasizes that while asynchronous programming has evolved, it has not necessarily become simpler, just better disguised.