Author Topic: UEFI and GPT (GUID Partition Table)  (Read 8759 times)

Martin Iturbide

  • OS2World NewsMaster
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3596
  • Karma: +34/-0
  • Your Friend Wil Declares...
    • View Profile
    • Martin's Personal Blog
UEFI and GPT (GUID Partition Table)
« on: February 27, 2015, 06:32:16 pm »
Hi

I try to find some discussion about UEFI and GPT on OS/2-eComStation, but I haven't find much.  It mostly says about UEFI, turn on the "legacy mode".

But I wanted to see if there had been any discussion of what can be possible solutions to implement/develop on OS/2-eCS. I haven't been interested on UEFI and GPT discussions on the past but now I want to learn more about it.

Any pointers?

Regards
« Last Edit: February 27, 2015, 06:36:28 pm by Martin Iturbide »
Martin Iturbide
OS2World NewsMaster
... just share the dream.

Dave Yeo

  • Hero Member
  • *****
  • Posts: 3633
  • Karma: +77/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #1 on: February 27, 2015, 07:23:40 pm »
Jonathan de Boyne Pollard claimed on usenet to be close to a solution some years back. Unluckily he seems to have disappeared and a lot of his pages are returning 404 errors.
http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/pcat-boot-process.html

Roderick Klein

  • Sr. Member
  • ****
  • Posts: 498
  • Karma: +14/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #2 on: February 27, 2015, 08:02:42 pm »
Hi

I try to find some discussion about UEFI and GPT on OS/2-eComStation, but I haven't find much.  It mostly says about UEFI, turn on the "legacy mode".

But I wanted to see if there had been any discussion of what can be possible solutions to implement/develop on OS/2-eCS. I haven't been interested on UEFI and GPT discussions on the past but now I want to learn more about it.

Any pointers?

Regards

Not much is written about this topic and OS/2 and you mention two things that are related. GPT is part of the UEFI standard I see Arca Noae has it on its roadmap as a research item.

https://www.arcanoae.com/roadmap/


Roderick

Martin Iturbide

  • OS2World NewsMaster
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3596
  • Karma: +34/-0
  • Your Friend Wil Declares...
    • View Profile
    • Martin's Personal Blog
Re: UEFI and GPT (GUID Partition Table)
« Reply #3 on: February 27, 2015, 09:50:54 pm »
Hi, thanks for the reply.

About ...
Quote
GPT is part of the UEFI standard
. Yes it is, but it seems that there is discussion that says that you can use GPT on non-UEFI machines. But I'm still not sure about it.

Talking about "GPT (GUID Partition Table)" it seems that the future is clearly that GPT is replacing MBR (Master Boot Record) because MBR has a 2TB limit. Since the future is obviously going to be to HDD 4TB bigger drives,  GPT is going to replace MBR.

So the options about GPT for OS/2-eCS on real hardware may be:
1) Implement/develop GPT for OS/2-eCS.  (hybrid MBR or full)
or
2) Use 4TB HDD or bigger, only as max 2TB drive (which I haven't tested to know if it works).

About Implement/develop GPT for OS/2-eCS, I also discussed on the chat and I was told as a very high level idea that it can be done by:  1) to update OS2DASD or 2) create a filter like partfilt.flt (like making a bypass of OS2DASD).

But I don't know if all the efforts of making a GPT driver only resides on modifying OS2DASD. (which I haven't said it is easy).

Just hearing some thoughts....
« Last Edit: February 27, 2015, 09:53:00 pm by Martin Iturbide »
Martin Iturbide
OS2World NewsMaster
... just share the dream.

Martin Iturbide

  • OS2World NewsMaster
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3596
  • Karma: +34/-0
  • Your Friend Wil Declares...
    • View Profile
    • Martin's Personal Blog
Re: UEFI and GPT (GUID Partition Table)
« Reply #4 on: February 27, 2015, 10:24:03 pm »
..uhm.. and I guess that LVM needs to be modifies too to support GPT ?
Martin Iturbide
OS2World NewsMaster
... just share the dream.

Dave Yeo

  • Hero Member
  • *****
  • Posts: 3633
  • Karma: +77/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #5 on: February 27, 2015, 10:35:13 pm »
os2boot and os2ldr as well, I guess for each file system that supports booting.

Roderick Klein

  • Sr. Member
  • ****
  • Posts: 498
  • Karma: +14/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #6 on: February 27, 2015, 10:37:48 pm »
os2boot and os2ldr as well, I guess for each file system that supports booting.

Hybrid MBR might be a solution but opinions seems to vary.

Roderick

Martin Iturbide

  • OS2World NewsMaster
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3596
  • Karma: +34/-0
  • Your Friend Wil Declares...
    • View Profile
    • Martin's Personal Blog
Re: UEFI and GPT (GUID Partition Table)
« Reply #7 on: March 02, 2015, 03:49:43 pm »
About UEFI
I had been reading there are some kind of UEFI applications that has the UEFI keys that acts like launcher for other applications. I don't know if that idea can be used to run OS2-eCS on an "UEFI ENABLED" machine.

I had read that there is GRUB with UEFI support and something else called UEFI Shim loader.

But maybe I'm understanding it wrong. I don't know if someone has more experience on this subject and can share what they have researched.

Regards
Martin Iturbide
OS2World NewsMaster
... just share the dream.

ivan

  • Hero Member
  • *****
  • Posts: 1358
  • Karma: +14/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #8 on: March 02, 2015, 10:08:22 pm »
Martin, it might be a good idea for you to talk with Jan van Wijk (DFSee) about this.  I think he would know much more than any of us.
 

walking_x

  • Jr. Member
  • **
  • Posts: 98
  • Karma: +0/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #9 on: March 03, 2015, 08:45:05 am »
About UEFI:
  • on PC - it always 64-bit.
  • it uses own interrupt handling for various things (USB keyboard, SATA devices, etc).
  • it provides only graphic 32-bit modes, for all, including "console". Graphic functions are extremly slow. Modern graphic protocol can supply pointer to video memory, but this is optional.
  • OS/2 kernel protected mode environment is incompatible with UEFI ... Also, UEFI uses 1st MB for own needs (GDT/IDT/page tables, etc) - but this space required for kernel too.
This mean:
  • we cannot use UEFI from kernel
  • we cannot use any hardware until the end first boot stage (when our own BASEDEV drivers becomes ready).
  • we cannot use BIOS int 10h, generally. Now it still present, but this is not guaranteed in the future. QEMU with TianoCore UEFI have no BIOS at all, for example. Therefore, the native video driver is also required!
Boot process must be changed seriously:
  • UEFI app loads all files for 1st boot stage (basedev drivers). Now this feature known as "preload" (in OS/4 kernel).
  • exit from UEFI and switching PC back to real mode to start kernel.
  • start basedev drivers (by using copy of it, was cached above). This requires some changes in boot file system or in kernel.
  • there are a plenty of other problems, but main is video...
  GPT itself is easy to implement. But we have another one trouble here - sector number in all IOCTLs - 32-bit... I.e., disk i/o in OS/2 limited to 2Tb. There is no way to read data above this border.
  So, David must design new IOCTLs and implement it in Danis/AHCI, then add changes to all disk i/o staff (DASD/LVM).

  Even to implement huge disk splitting (3Tb -> 2Tb+1Tb) - like it was done in partflt - 1st stage still required (64-bit sector number in Danis).

  And, yes, hybrid table can be used too, but this is dangerous and this "hack" limited to max of 3 (primary) partitions.

  This is the picture - how I see it ;)
« Last Edit: March 03, 2015, 08:47:17 am by walking_x »

Martin Iturbide

  • OS2World NewsMaster
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3596
  • Karma: +34/-0
  • Your Friend Wil Declares...
    • View Profile
    • Martin's Personal Blog
Re: UEFI and GPT (GUID Partition Table)
« Reply #10 on: March 03, 2015, 03:10:09 pm »
Thanks walking_x  for sharing your thoughts and opinions.

In my limited understanding of the very deep components of OS/2, it will mean that to support UEFI (without legacy mode) changes will have to be done on the OS/2 kernel and loader.
Martin Iturbide
OS2World NewsMaster
... just share the dream.

Roderick Klein

  • Sr. Member
  • ****
  • Posts: 498
  • Karma: +14/-0
    • View Profile
Re: UEFI and GPT (GUID Partition Table)
« Reply #11 on: March 03, 2015, 10:07:21 pm »
Thanks walking_x  for sharing your thoughts and opinions.

In my limited understanding of the very deep components of OS/2, it will mean that to support UEFI (without legacy mode) changes will have to be done on the OS/2 kernel and loader.

I do not know if an EFI loader that you create if you can reimplement legacy support (a BIOS basically).

Roderick

Martin Iturbide

  • OS2World NewsMaster
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3596
  • Karma: +34/-0
  • Your Friend Wil Declares...
    • View Profile
    • Martin's Personal Blog
Re: UEFI and GPT (GUID Partition Table)
« Reply #12 on: March 04, 2015, 02:25:41 am »
I do not know if an EFI loader that you create if you can reimplement legacy support (a BIOS basically).

That is why I was asking if anybody knows something about Shim. I don't know if I'm missintepreting the use of Shim, maybe it is for other thing.
Martin Iturbide
OS2World NewsMaster
... just share the dream.