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



Reply via email to