On 14 July 2016 at 22:16, Reinoud Zandijk <reinoud(a)netbsd.org&gt; wrote: Yes, I take your point here - if you're going to be different to the de facto standard you might as well rethink a whole bunch of assumptions. With lowRISC we're very interested in pursuing new hardware and software features, and going beyond just replicating something that looks like a typical ARM/MIPS SoC. This is the reason for our focus on minion cores and tagged memory. That said, there are major benefits in supporting the integration of traditional devices and in reusing as much operating system and driver code as possible. As you point out, if you try too hard to be fully compatible with everything existing today you'll end up looking just like everything that exists today. There's hopefully a sensible balance somewhere between the two extremes of throwing every existing out of the window and in unambitiously recreating precisely a standard current-day SoC platform! At the RISC-V workshop last week, Krste suggested the model for proposals to the RISC-V Foundation be that these proposals are in-line with the minimal spirit of the RISC-V ISA and that they are accompanied by implementations. I think a similar approach would be useful with lowRISC. You're certainly keenly aligned with the focus on simplicity, but it's hard to truly judge a proposal and ensure all the details have been thought through until it has been implemented. There's a bit of a chicken/egg problem as I can understand reluctance to implement even a qemu/spike model of an idea until you think it's likely to be accepted. I do think trial implementations are key though. I hope work like the xv6 port will also help to provide a very simple minimal OS that might be a good target for experiments that would be difficult in a much larger codebase such as Linux or *BSD. Best, Alex