> Can somebody explain to me why async IO is so important and why it is better than using the operating system scheduler? You still do. The difference is with

> Can somebody explain to me why async IO is so important and why it is better than using the operating system scheduler? You still do. The difference is with thread-based IO you block a task until the IO scheduler is done with one operation, while with async IO you block a task until the IO scheduler is done with any operation. The reason why async can be more efficient is that you have fewer tasks and possibly less task-housekeeping-overhead. It's important to note that disk I/O generally has poor support for asynchronous operation (because disk I/O traditionally meant that high I/O concurrency brutally murders throughput, which has changed). It's something that's being worked on for Linux, though.