Installing and running UEFI DUET
Jonathan de Boyne Pollard
bootable in the old PC/AT way. Maybe the osFree people working on their
FREELDR will work on a version that can run on EFI systems. (If you're
reading this: You won't have to worry about switching into protected
mode, using mini-FSDs, enabling A20 gates, or any of that chaff. The
firmware will do all that for you.)
It's possible to make an old PC98 machine into a Poor Man's EFI machine,
using DUET ("Developers' UEFI Emulation Tool"). This is, basically, a
program image that is booted as if it were an old-style PC/AT operating
system, that loads up a reference implementation of EFI firmware and
displays the EFI Boot Manager. One can then run EFI "pre-boot"
applications (from Microsoft's old DISKPART.EFI to the stuff that one
can now get for Intel Macintoshes) and bootstrap EFI operating system
boot loader programs on top of it, just as one would on a true EFI
system. There is even the good old built-in UEFI Shell, complete with
text editor, file manipulation tools, and whatnot. The downside is
that, as supplied, DUET's own bootstrap mechanism leaves a huge amount
to be desired. If you've ever used it, you'll know that you have to
pick the right version from about eight different program image files,
otherwise it will mysteriously hang or reboot. You also have to,
somewhat madly, use different names for the program image file according
to whether you are using FAT12, FAT16, or FAT32. It's quite nutty.
Not any more.
To complement the MBR with EFI partition table support, that I mentioned
a couple of weeks ago, I've written a TAU boot loader for DUET. This
uses exactly the same bootstrap process as my boot manager, except that
in the final stage instead of loading my Boot Manager it loads up DUET
instead. It allows you to use any filename you like for the program
image, and it doesn't matter if one doesn't use the image that exactly
matches the FAT width of the containing disc volume. (You've still got
to pick the right image for x86-32 versus x86-64, though. I cannot do
anything about that.)
I now have here, thanks to both, a system with PC/AT firmware that has
an EFI partition table, an EFI System Partition, and DUET. It
bootstraps directly to the EFI System Partition (thanks to the MBR with
EFI partition table support) and thence into DUET (thanks to the TAU
boot loader for DUET). So it goes from POST straight to the EFI Boot
Manager, with nothing more than a few copyright messages along the way. (-:
I've put up the step-by-step process of how I did it on a page that
you'll find hyperlinked-to from the TAU System Utilities page on my own
WWW server. I've subtly named the hyperlink "Instructions for
installing TAU Boot Manager or UEFI DUET onto a system volume". All of
the tools for following the procedure are in the latest TAU System
Utilities archive.
Once one has booted a system into x86-64 DUET one, according to
Microsoft, can install Windows NT 6.1 ("Windows 7") using its x86-64 EFI
installer, rather than its PC98 installer. The EFI installer will
install the EFI versions of Microsoft's Boot Manager and Boot
Configuration Data, into an EFI System Partition; something that is not
possible to do with the PC98 installer. (Beware: Windows 7 requires a
bona fide EFI System Partition for this trick, not a Poor Man's
equivalent such as a System Reserved Partition.) Thence one can install
Linux with ELILO and other EFI-bootable operating systems, and have them
all on the menu of DUET's EFI Boot Manager, which becomes the primary
boot manager for the system. Combine all that with an EFI partition
table, and you get (a) no more headaches caused by the differences
between secondary and primary partitions; (b) no "hybrid MBR"
partitioning nonsense; (c) no more 2TiB disc limit worries; (d) no more
problems from boot managers that work as MBR computer viruses; (e) no
more dealings with "MBR disc signatures", "LVM info sectors", or other
such nonsense; and (f) the EFI Shell accessible at boot time. Oh: and
you get 36 character Unicode names for your partitions, too. (-:
Unfortunately, one cannot boot IBM OS/2 or eComStation from the EFI Boot
Manager. They don't have the right kind of operating system boot
loader. So I encourage you to prod the osFree and the eComStation
people to make EFI versions of OS2LDR and FREELDR.
Roderick Klein
I send you an email but did not receive a reply. We are looking at
getting EFI support for OS/2 (well eComStation). But we would need to
work togheter on that. I'm working on setting up a team for that.
Just like we have for SNAP (http://svn.ecomstation.nl/snap).
Your knowlegde on EFI on such a team would certainly be welcome.
Roderick Klein
Mensys
Jonathan de Boyne Pollard
Did you look in the right mailbox? (-: I sent a reply -- twice -- to
the mailbox that you used in the From: header in your very post here.
Roderick Klein
Jonathan de Boyne Pollard wrote:
I checked my inbox, trash can and spam filters at our ISP but could not
find it.
Can you send it again please ?
Roderick
Jonathan de Boyne Pollard
I've sent it two more times.