My first post to 9fans; Hi! I am currently running 9Front on real hardware (mini-itx board with an Atom CPU), I also run 9Front using Virtualbox. I have had issues getting regular Plan 9 to install using Virtualbox. I know it wasn't a problem in the past. Anyway, as I was walking through some sites related to this I found this post:
"I had a look at Plan 9 and I can only say that their idea of real mode is miles away from Intel's. Plan 9 crashes because it calls BIOS with an environment that only vaguely resembles real mode in that CR0.PE is 0, but segment limits and attributes are totally all over the place. For example they leave the 'B' bit for the stack segment set, which causes rather interesting behavior of instructions that manipulate the stack. That then triggers an extremely obscure bug in VirtualBox which probably affects no other OS on the planet. The Plan 9 folks should probably re-read chapter 9.9.2 (Switching Back to Real-Address Mode) of the Intel 64/IA-32 SDM (Volume 3) and implement their mode switching code the way Intel says they should. This is their code in sys/src/9/pcboot/realmode0.s." The post is located at: https://forums.virtualbox.org/viewtopic.php?f=4&t=52431 It was one of very few posts that contained any technical information whatsoever. Most posts I come across just say that the installation hangs. I do not know if the above is of any help or even useful in any way, but I thought I'd post it here, since it might help. -- Rikard Lang
