I use QEMU every day for testing my new operating system: https://github.com/awesomekling/serenity https://github.com/awesomekling/serenity QEMU has just the r

I use QEMU every day for testing my new operating system: https://github.com/awesomekling/serenity https://github.com/awesomekling/serenity QEMU has just the right mix of performance and hackability that I need for my "printf debugging" workflow :) (I've used Bochs a lot, too, which is more hackable, but far less performant.)