[PC-BSD Support] UEFI Boot Question

Bret Busby bret.busby at gmail.com
Wed Oct 9 09:31:14 PDT 2013

On 09/10/2013, Jacob . D <frag-artists at cox.net> wrote:
> What you just referenced is a common mis-belief/hype/FUD
> Secure Boot is just a firmware module of UEFI, and not the whole thing.
> If you have a fairly recent computer you can go to the "Advanced"
> section of your BIOS and adjust three settings in particular,
> change from windows to "other OS" , enable CSM  and, finally  enable
> "legacy OP-Rom"
> also, if you want to dual boot PC-BSD and windows together and have
> assistance in doing  this with a GUI,
> you can try this program,
> http://neosmart.net/EasyBCD/
> it is free.
> you can use this for booting Linux and Windows together too!
> I work in the "Puppy Linux" community too, and wrote this article, it
> may help out alot!
> Please share, to resolve this stupid hype!
> http://puppylinux.org/wikka/UEFI
> Thanks!
> _______________________________________________
> Support mailing list
> Support at lists.pcbsd.org
> http://lists.pcbsd.org/mailman/listinfo/support

Okay then - now, this appears to have now got more complicated.

>From the material that you have referenced, it appears to me, that
either the Microsft Windows 8 / UEFI installations are MS Win8 only,
or, they can be configured to implement CSM, which apparently involves
using the BIOS/MBR system, instead of the UEFI/GPT system.

The computer that I am currently using, is a Dell Inspiron 580, which
came with MS Win7 installed, and I subsequently installed onto it,
Ubuntu 10 or 11 or 12 LTS, and Debian Linux 6.

With the PC-BSD restriction (which, I understand, applies equally to
each version/distribution of BSD) that it be installed in a primary
partition, the MS Win7 installation took three of the four possible
primary partitions (involving BIOS and MBR) - one for the Dell
recovery thing, one for the operating system, and, I do not remember
what the other one is.

To create an extended partition, takes up a primary partition. Thus,
all four primary partions became used, with the MS Win installation,
and, the creation of the extended partition.

So, on a computer with MS Win7 installed, it can't be done, to both
instal PC-BSD and have an extended partition (which allows the logical
partitions for other operating systems, such as Debian Linux, that I
am currently using, and swap partition and data partitions, etc).

Whilst I rarely use MS Win7, I sometimes boot into it, as a particular
software application, that I sometimes use, is available only for MS

Now, from my understanding, a UEFI/GPT system, overcomes the
restriction of four primary partitions, that a BIOS/MBR system
suffers, allowing for up to 128 partitions, with no differentiation
between primary and extended partitions, and, allows partition sizes
and hard drives, of 2TB and more.

>From the material that you referenced, four classes of UEFI, exist;
Class 0 - Legacy BIOS
Class 1 - UEFI with CSM only
Class 2 - Both UEFI and CSM
Class 3 - UEFI (No CSM)

with the first three using MBR, with the maximum of four primary partitions.

So, from what I understand, for me to have a Windows computer with
Debian Linux (to which, at present, with Debian 6, I am most
accustomed) and PC-BSD, installed and bootable, I need to have the GPT
system, which is part of, and / or, requires, UEFI; in this scenario,
apparently, UEFI Class 3.


Class 3 UEFI bios does not have any CSM and therefore there are no settings.

Class 3 UEFI bios is 64 bit windows 8 secure boot only forever.  No
legacy, No CSM, No windows 7.

So, the question/contention/issue arises, as to whether UEFI /GPT
allows any operating system other than MS Windows 8, to be bootable,
and, thence, whether UEFI/GPT (and the benefit of the removal of the
limit of four primary partitions) can allow PC-BSD (and, other
operating systems, such as Debian 6, but, this list relates to PC-BSD)
to be installed, and, to be bootable.

A computer that I am considering buying, is the Acer Aspire
V3-772G-747a161TBDWakk as described at
which I had previously found somewhere (I can't find the information
again, tonight) to be expandable to 32GB RAM, which, with the other
specifications, should be adequate to run the operating systems that I
want to run, if it allows the installation of the operating systems,
and, allows the different operating systems to boot (one at a time - I
am not intending to run multiple operating systems on the same
computer, concurrently, although it apparently has sufficient
resources, to do that, using something like VMWare).

But, buying "on spec" - by the specifications, and, without seeing and
trying the computer, I do not know whether it would be possiblke, to
achieve what I want to achieve - to have a computer, with MS Win,
PC-BSD, and, Debian Linux 6, each installed and, bootable (and,

And, the information that you referenced, whilst interesting,
unfortunately, confused me, even more.

I am still trying to come to terms with the UEFI/GPT concept (I am
aware that it apparently, has been around, for about a decade, now,
and, has been progressively implemented), but, from what I had read,
apart from the "secure boot" obstruction, it appeared a way to achieve
what I want, but, it appears that, to have the UEFI?GPT
implementation, from the information that you referenced, the "secure
boot" installation must be imposed.

So, unfortunately, I am none the wiser.

Bret Busby
West Australia

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
 Chapter 28 of Book 1 of
 "The Hitchhiker's Guide to the Galaxy:
 A Trilogy In Four Parts",
 written by Douglas Adams,
 published by Pan Books, 1992


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