It's not over 4TB, it's for over 2TiB. MBR tables have a 32 bit bitfield
for addressing sectors - so 0x100000000 (since sector 0 is also
accounted for) sectors multiplied by 512 bytes per sector, divided by
1024^4 bytes per TiB, gives us exactly 2 TiB. GPT introduces 64 bit
bitfields for sector numbers. Individual devices may also have different
sector sizes than 512 bytes. There's plenty of HDDs popping up since
early 2010s that have 4096 bytes per sector, but they support being
addressed as 512 byte logical sectors for the convenience of whatever is
trying to access the disk.
W dniu 20.12.2025 o 16:09, Roger via Freedos-user pisze:
Clarification, if you're unaware, partition layouts can either be the
old MBR (legacy/old DOS) partition layout or GPT newer partition
layout, with support for >4TB and required for EFI boot methods. MBR
can only boot old legacy/DOS, no EFI. GPT can handle both, requiring
a workaround for booting MBR related operating systems, however
requires BIOS CSM (legacy BIOS support) enabled when booting MBR
related operating systems.
On Sat, Dec 20, 2025 at 9:42 AM Roger <[email protected]> wrote:
Windows 11 (unlike Windows 10) by default installs to EFI partition.
I found out the hard way, only use bcdboot.exe for reinstalling the
Microsoft Windows 11 EFI partition and Microsoft Windows 11 relevant
contents into the EFI partition. If I'm not mistaken, bcdboot will
automatically call the relevant EFI related parts of "bootrec /scanos"
(bootrec.exe), so not needed to run scanos functions. Trying to use
MBR bootrec.exe executable will cause Windows 11 to not boot, and/or
display the ugly blue repair screen. (The brief process for deleting
and creating the Windows 11 EFI, remove/create the initial FAT32
partition, boot into the Windows 11 repair, use diskpart for
creating/finding the EFI FAT32 partition and assigning a letter if
needed, exiting from diskpart and running bcdboot incantation for
reinstalling the Windows 11 EFI partition contents. If any other
Windows operating system has been installed via the EFI method (not
MBR method), this process should automatically create a boot menu for
those other Windows EFI bootable operating systems.
Windows 10 and older operating systems, will call for using
bootrec.exe, working with and install MBR related functions, again,
not compatible with Windows 11. You'll encounter a lot of
instructions on the Internet directing for utilizing bootrec.exe in
tandem with bcdboot.exe.
Another hiccup I ran into, likely Windows 10 can be installed via
both, MBR and EFI; or Windows 11 just installs two separate EFI
partitions within one drive, likely for MBR/EFI compatibility. Weird.
Microsoft only wants and needs you using their latest and greatest
operating system!
Roger
On Fri, Dec 19, 2025 at 7:43 PM Tomas By via Freedos-user
<[email protected]> wrote:
On Sat, 20 Dec 2025 01:31:44 +0100, Karen Lewellen wrote:
exactly which Linux?
Well, I only have recent experience with Ubuntu, but it has worked the
same in all others I have tried, for quite a while now.
/Tomas
_______________________________________________
Freedos-user mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/freedos-user
_______________________________________________
Freedos-user mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/freedos-user
_______________________________________________
Freedos-user mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/freedos-user
