Upgrade BIOS/MBR to BIOS/GPT

I think I know the answer to this question, but I’m just looking for confirmation.
Normally you need an UEFI system to have a GPT partition table, but I think it’s possible to have a GPT partition table in a BIOS (legacy) system? But even if that is correct, I don’t think it would work in my setup - I explain…

I currently have a 1TB hard drive with Windows XP on it (in a 250GB primary partition). The partition scheme is MBR, Windows is 32 bits and pre-dates UEFI/GPT.
I want to install Manjaro Cinnamon (3 partitions ‘/’ ‘home’ ‘swap’) a long side Windows XP (dual-boot).
If I would manage to update MBR to GPT, Windows would probably not boot anymore - Am I correct in this assumption?

It is possible to have GPT in combination with a legacy BIOS, yes. All it takes is that you create a small partition of about 2 MiB in size, and of the partition type bios_grub, and marked with the boot flag. This partition must not be formatted, because it is a placeholder for GRUB’s core.img code, which is too big to fit in the MBR and would otherwise overwrite the starting boundary of your first real partition.

You don’t need GPT for that. An MBR partition table does support more than 4 partitions, as long as one of the four available primary partitions is an extended partition container. This container can then act as a secondary partition table for logical partitions.

Now, if you were to decide to convert your MBR partition table into GPT, then Windows XP won’t be able to boot from it anymore. So my recommendation is to simply stick to the MS-DOS MBR partition table that you have.

Further reading… :arrow_down:

Thanks for confirming, and yes the easiest would be to just install Manjaro in logical partitions. I was just wondering if there was any advantage of a GPT partition table (Other than removing the 4 primary partition limit and HDD size limit)

If I was to re-install Windows XP (I have a slip-streamed ISO), could I do it in a UEFI/GPT or MBR/GPT partition scheme? and then install Manjaro? I’m doubtful - Windows would probably insist on creating an MBR

Negative. The x86-32 and x86-64 versions of Windows XP cannot be installed on a GPT-partitioned drive, and cannot boot from it either. The only version of Windows XP that supported GPT was the version for IA64, i.e. the 64-bit Intel Itanium and Itanium2 processor family.

:man_shrugging:

I thought that was the case, thanks Frank for confirming. I will just stick with the MBR partition table.
From what I know, Linux systems don’t care if they installed in a ‘Primary’ partition or a ‘Logical’ partition so I may just create an extend partition and place all the Manjaro partition (root, home, swap) within.
Just one more question: Is there a way to create a swap file instead of a swap partition during the install? :thinking:

That is correct, and that is how it had always been on dual-boot machines that had Microsoft Windows installed. Windows would claim the first primary partition, and GNU/Linux ─ or any other UNIX ─ would be pefectly happy being installed in logical partitions inside the extended partition container. :wink:

Yes, there is ─ the option is available in Calamares. :wink:

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