Not sure how well this was covered in the Slackware Documents but I figured I'd share anyway.

For the curious, yes, you can use GPT on a BIOS PC the same as a UEFI system though there is some minor differences.

For one, there is one thing you'll need to realize:

A disk partitioned with GPT on BIOS can not boot Microsoft Windows in Dual-Boot, so don't even try. Just use a secondary HDD/SSD and use the BIOS boot selection feature for multi-booting.

Now first things first...

You're going to need a special partition to be created using gdisk, cgdisk or parted called a "BIOS Boot Partition".

All three of these utilities can create one of these. You'll need to select the Partition Type as EF02 type.

It doesn't need to be large either. So allocating at least 5-10MB is more than enough.

I borrowed this method from the Gentoo handbook with my own mods:

/dev/sda1 - BIOS Boot Partition - 5MB
/dev/sda2 - Linux EXT2/3/4 for /boot - 100MB
/dev/sda3 - Linux swap - 2-4 GB unless you're compiling a lot of software then 6-8 GB.
/dev/sda4 - Linux EXT3/4, JFS, or ReiserFS /(root file system) - remaining disk space

I left BtrFS off for a damn good reason. Don't use it! It's still experimental. XFS was left off due to issues with power loss and data corruption issues.

This method is useful for using Grub2 mostly, if not only. eLILO which is Slackware's default bootloader really doesn't require this. Not sure if this works with the syslinux/extlinux bootloader.

You don't technically have to mount the BIOS Boot Partition, but if you want you could always possibly mount it under /boot/bios in reference to how /boot/efi is mounted if you use an EFI System Partition for sh*ts and giggles.

Actually, elilo is only used instead of lilo during installation of Slackware64-14.1 in case of an EFI firmware, because then lilo doesn't work. In that case a GUID partition table (aka GPT) is mandatory but can still be used instead of the Master Boot record (MBR) for BIOS firmwares. In fact Slackware ships several boot managers: lilo, elilo, grub2 and {sys,ext,iso,pxe}linux.

To boot the Slackware64-14.1 intallation DVD grub2 is used instead of isolinux in case of EFI firmware (isolinux 6 can do an EFI boot but is not stable enough yet to be included in Slackware).

It is. A quick search and you would have found it.

Thanks Ruario. Oh well at least its been re-shared.

[resurrecting six-month-old thread]

I'm sorry to say but your document is neither complete nor clear regarding the installation of Slackware with GPT on BIOS. You gloss over the partitioning steps required, which might be good enough for those who understand how to partition with parted, gdisk and cgdisk, but is nowhere near good enough for what purports to be a step-by-step guide submitted to docs.slackware.com. Please don't take this criticism personally; I know how difficult it is to write documentation which makes no assumptions about the reader's level of expertise. That's why I don't submit tutorials, even though I have quite a collection for my own use now. Your document should be entitled "How to install a bootloader with GPT disks on non-UEFI systems", because that's all you cover. You do not cover installation of Slackware with GPT on BIOS.

Since yesterday evening I have been pulling my hair out trying to install first Slackware and then Salix on a virtual machine, using parted to create the partitions on a GPT virtual disk. I am reliably informed on each occasion that Slackware cannot find any Linux partitions, and needless to say installation of Slackware is stopped there and then, dead in its tracks.

I do the following to create the partitions:
Perhaps I should be using cgdisk, but I wanted to learn parted, and parted is included with the Slackware installer so I presume it can be used. Perhaps as well a GPT BIOS combination doesn't work in Virtualbox, but in either case, your help document should be much more comprehensive in its coverage or modest in its claims. It is neither, which leaves the rest of us still scratching our heads and going to the Gentoo and Arch wikis for further assistance.

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gezley,

I've had problems before with parted and gparted that caused them to not mark the partition type code correctly - ext3 partitions with NTFS codes and so on. It's caused me some trouble using the same external drive in Windows and Linux. So, I just tried installing Slackware in Virtualbox and had the same issue as you. When I checked gdisk, parted had marked the partitions as 0700, which is "Microsoft Basic Data," even though I had told parted to make Linux partitions and had run mkfs.ext4 on them. Changing to 8300 with gdisk made the Slackware installer "see" the partitions as Linux partitions. You might want to try that if you haven't got it working yet.

Thank you Armenore. I had the same Microsoft Basic Data issue and indeed I turned to gdisk to solve it, but the VM still refuses to boot. I ran out of time in the end and gave up. Perhaps another day.