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Installing and running UEFI DUET

Cross-posted to 4 groups.

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One cannot boot IBM OS/2 directly from EFI firmware.  IBM OS/2 is only 
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.

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Thread

Installing and running UEFI DUET Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-07-10 22:20 +0100
  Re: Installing and running UEFI DUET Roderick Klein <rwklein@xs4all.nl> - 2011-07-27 17:14 +0200
    Re: Installing and running UEFI DUET Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-07-28 15:46 +0100
      Re: Installing and running UEFI DUET Roderick Klein <rwklein@xs4all.nl> - 2011-07-29 17:18 +0200
        Re: Installing and running UEFI DUET Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups@NTLWorld.COM> - 2011-08-01 11:15 +0100

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