One of my machines has a 3 TB HD setup to triple boot into Mint 14 (Ubuntu 12.10 variant), Slackware 14.1 and Arch Linux. The HD is formatted using the GPT/Guid system. The Grub2 technically "belongs" to the Linux Mint install but is used to triple boot all 3 systems. Setting it up about 1 year ago was an extremely painful procedure and required 2-3 days of wrestling with it, and tweaking it, to allow it to recognize the Slackware and Arch installs; it would always recognized the Mint Linux install easily.

I need to be able to pass VGA/VESA modes to Slackware and Arch. I use Slackware and Arch from the command line and therefore console resolution and font size are important factors.

We had a discussion on this in LFS, but it'll translate to Slackware fine.

http://www.linuxquestions.org/questi...ed-4175488179/

You'll have to edit /etc/default/grub as shown in my example with the lines specifically for GRUB_CMDLINE_LINUX_DEFAULT and GRUB_CMDLINE_LINUX to pass the vga=# setting. This will pass the appropriate vesa/vga settings to the framebuffer.

That should translate to Slackware just fine but doesn't Arch have enough systemd stuff in it now that it will be compromised by the fact that Grub2's "nomodesetting" doesn't work in such systems (apparently get's overriden in a headlong rush to faster boot times)?

It should work with Arch, but yes, due to how systemd works, it might be hit or miss, however, because most of these are kernel settings, it should be init-independent.