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Re: [bug #46716] Protective MBR partition is not marked as bootable
From: |
Thomas Schmitt |
Subject: |
Re: [bug #46716] Protective MBR partition is not marked as bootable |
Date: |
Sat, 19 Dec 2015 20:37:04 +0100 |
Hi,
Andrei Borzenkov wrote:
> a) are we sure every EFI system out there accepts MBR (Apple?)
At least my favorite layout (see my recent mail
address@hidden) is explicitely
promised by UEFI 2.4, "5.2.1 Legacy Master Boot Record (MBR)".
The Apple problems in the blog of mjg, who invented the
ISOLINUX+GRUB2 layout as of Fedora or Debian amd64, seemed
rather related to the need for HFS(+). The Macs made him use
MBR partition type 0x00, IIRC.
http://mjg59.dreamwidth.org/11285.html
(and older ones from within his endeavor)
Since Vladimir provided HFS+ for libisofs, he might have some
Apple knowledge in reserve.
> b) GPT has nice feature of self-identifying block size.
How this ?
There are no block size fields in the GPT storage format.
UEFI 2.4, 5.3.1 frightens me by
"The device may present a logical block size that is not 512 bytes long."
which would not play well with our habit to create image files
which only later get onto some device.
i wrote:
> > Nevertheless, your overlapping layout would have the appeal of
> > giving a mountable partition:
> > [...]
> > It would travel on the ticket that EFI shall ignore MBR partition
> > type 0x00.
> I'm not sure where this assumptions comes from. EFI does not say
> anything about other partition types,
UEFI 2.4, 5.2.1 Legacy Master Boot Record (MBR)
"A Partition Record that contains an OSType value of zero or a
SizeInLBA value of zero may be ignored."
Table 14 shows OSType as byte at offset 4 in the MBR partition
entry. Aka "partition type".
The question is how far this ignoring goes.
ishoybrid+GRUB2 as of mjg hopes for effective non-existence
as far as EFI and its do-not-overlap demand is concerned.
Have a nice day :)
Thomas
- Re: [bug #46716] Protective MBR partition is not marked as bootable, (continued)
Message not available
- Re: [bug #46716] Protective MBR partition is not marked as bootable, Alexander E. Patrakov, 2015/12/19
- Re: [bug #46716] Protective MBR partition is not marked as bootable, Alexander E. Patrakov, 2015/12/19
- Re: [bug #46716] Protective MBR partition is not marked as bootable, Thomas Schmitt, 2015/12/19
- Re: [Bug-xorriso] [bug #46716] Protective MBR partition is not marked as bootable, Andrei Borzenkov, 2015/12/19
- Re: [bug #46716] Protective MBR partition is not marked as bootable,
Thomas Schmitt <=
- Re: [Bug-xorriso] [bug #46716] Protective MBR partition is not marked as bootable, Andrei Borzenkov, 2015/12/20
- Re: [bug #46716] Protective MBR partition is not marked as bootable, Thomas Schmitt, 2015/12/20
- Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Thomas Schmitt, 2015/12/20
- Re: Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Thomas Schmitt, 2015/12/20
- Re: Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Alexander E. Patrakov, 2015/12/20
- Re: Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Alexander E. Patrakov, 2015/12/23
- Re: Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Thomas Schmitt, 2015/12/23
- Re: [Bug-xorriso] Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Andrei Borzenkov, 2015/12/24
Re: [Bug-xorriso] Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Andrei Borzenkov, 2015/12/20
Re: Test Proposal for [bug #46716] Protective MBR partition is not marked as bootable, Thomas Schmitt, 2015/12/20