My 2c on this. This is mostly obvious & some points are covered in the thread already. (1) Having a standard serial port that is present on all hardware, located at the same address everywhere, same model everywhere, easy to drive, available as soon as possible after boot -- just that one thing would be a massive improvement over ARM. (2) A single OS image[*] should be able to boot on every piece of hardware. Like on PCs. I'm not going to say how you should achieve this, but again taking ideas from PCs may not be a bad idea. I'm thinking: some tables describing memory (like E820), discoverable and self-describing hardware (PCIe, USB, etc), ACPI tables[**]. For the server case, a UEFI bootloader that loads the kernel and provides services, probably rendering the whole memory map problem moot. (3) It's a nice idea to reuse infrastructure that Linux, BSD, Windows already have. Those OSes can read ACPI tables, the code already exists to parse PCI config space, etc. Reusing that code means you don't need to write something else and argue why your thing should go upstream instead of the thing which is already upstream. There was some discussion about a "config string", but that sounds like a terrible idea - see point #3. The kernel developers absolutely do have a say in this when the architecture is brand new and you can choose not to do something. Rich. [*] I mean a single OS image compiled for a specific bit width variant of RISC-V. [**] I would say device tree, but ACPI is an actual standard, cross platform, and also includes a way to run interpreted code which is useful. MSFT and Red Hat have pushed hard for ACPI in the ARM server space -- and implemented it -- with at least some (limited) degree of success. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top