On Sun, Jul 5, 2015 at 7:05 AM, Peter Kay <syllops...@syllopsium.co.uk> wrote: > OK, I should be more specific - what I got working was an OpenBSD install on > a GPT disk which included Windows 7 installed in MBR mode. This involves > some nasty hackery with OpenBSD fdisk, and was done at the time because I > thought I'd be installing OS X on the same disk. > > What I haven't explicitly got working is Windows 7 in GPT mode on a GPT > disk, alongside OpenBSD, because my BIOS only supports the ancient 32 bit > EFI 1.1 (Intel server motherboard) > > To recap : > > Vista SP2 x64 supports GPT installs, as does Windows 7 x64 or better. > OpenBSD does not understand GPT at all > FreeBSD does > NetBSD did/does(?) But only to the point of recognising, not installing on > the disk. The worst of all worlds. > > When a GPT disk is created, in addition to the GPT format, it creates a > 'protective MBR' where up to the first 2TB (limit of MBR) is covered by a > partition of type 0xEE. This is to stop older programs overwriting bits of > the GPT disk. > > It is possible to manipulate this protective MBR, and therefore install > OpenBSD. Windows is remarkably tolerant of weird hard disk partitioning > formats. OpenBSD doesn't know, or care. Linux does, however - it will see > and use GPT. > > I run everything off Xen at the moment, which does now have an EFI BIOS > supporting GPT I believe. It will take me a little time to allocate a disk > image to install both 7 and OpenBSD on and test if it can be done. I'm > fairly certain it can be done, but off the top of my head I can't remember > if a GPT install of 7 has the same boot capabilities as MBR. > > In any case, there you go. A GPT disk can definitely support a hacked on MBR > install of 7 and OpenBSD. GPT with GPT Windows and MBR OpenBSD I'd have to > double check > > PK
Okay, thanks for the information. What I had was MSW8 set up on a straight GPT formatted, UEFI BIOS, DRM enabled netbook (HP Pavilion-something). Took a restore DVD set and confirmed that I can re-install MSW8 by just walking on top of whatever is on the disk. Couldn't find options to set up MBR or to install to a pre-partitioned disk. So I'm doing entirely without MSWindows right now. (No feelings hurt, I prefer it that way, really, except there's a project I eventually want to pick back up involving the SH3 processor, and Renesas seems to only support tools that run on MSWindows. And that kind of stuff. If I need it bad enough I suppose I can buy a boxed MSWOS, but I'd rather not pay MS any more money than I have to.) I've got openbsd running in the inboard drive, MBR/DOS partitioned. Also got it running outboard (USB3, ugh). That is another possible option, really, when I need MSWindows, run openbsd from outboard (and be careful not to pull too hard on the cable ;-). I've enabled the current kernel GPT support (re-compiled, etc.), but I haven't been able to tell whether that actually buys me anything without GPT utilities. (My son has a similar, newer HP Pavilion netbook with Ubuntu installed in a GPT partition, but he won't let me boot openbsd outboard to try to see what GPT support in the kernel enables. No time to let me play on it, he says.) So, I'm planning to temporarily move things to the outboard drive and re-install MSW8 this week to see what happens. I don't think I'm going to go so far as to spoof the MBR, however. I'm thinking, just (1) shrink the MSWindows partition, (2) make a partition in the empty space, (3) and see if I can get disklabel in a bsd.rd image built with GPT enabled in the RAMDISK confiiguration to find that partition and let me install there and boot from it. If that fails, my tests so far indicate that the outboard openbsd running the GPT enabled kernel is still not going to let me see the GPT partitions in the inboard drive, but I'll check that, of course. If it does, I'll try something like unpacking it by hand. (Even more opportunities to learn from failures, of course. :) If I get stuck, I'll probably set GPT aside for several months and focus on getting the WIFI on this thing running. In fact, if someone would tell me that what I'm trying to do isn't supported yet, I'd be happy to work on the WIFI first. I'd like to be able to access the net from this box at work, and they don't want me plugging into the wired LAN, but have no problem with logging into the wifi network. -- Joel Rees Be careful when you look at conspiracy. Look first in your own heart, and ask yourself if you are not your own worst enemy. Arm yourself with knowledge of yourself, as well.
