Boot: "CORE" Edition: Alternative to syslinux - saving up to ~200kB of space on FDDs.

[kkarhan]

As @landley pointed out, syslinux has perl as dependency and as per observation is consuming quite a lot of space.

So far, thanks to @sweetaibelle the following options are on the table:

• mlb - Minimal Linux Bootloader
  • doesn't support initramfs.
• tiny-floppy-loader.
  • also expects the initramfs to be embedded in the kernel, making things more complicated.
• simpleboot may be interesting.
  • it's basically a more simpler alternative to bootboot and easyboot with near-zero dependencies.
• limine-bootloader doesn't seem to be more compact than syslinux and only adds complexity when comparerd to syslinux in terms of config.

Options I've disregarded after looking into:

• LILO is kinda nope due to being abandonware.
• systemd-boot would likely need way more space than syslinux which already eats like 200kB doing nothing but yeet kernel and initramfs in memory.
  • It also requires UEFI to boot which is basically not available on vintage machines running i486 - SX and up.
• loadlin is just a chainloader requiring DOS.
  • gujin is basically a like loadlin.
  • As is masterbooter.
• AirBoot requires chainloading GRUB to boot Linux.
• u-boot is an even bigger mess than syslinux just by the looks of the README file.
• barebox which looks like a cursed mashup of u-boot and busybox with the cherry on top of mixing GPLv2-only and GPLv2-or-later code...
• wolfBoot will basically only work on select systems and is more of a "Secure Boot" aka. CensorBoot implementation which by Microsoft's own admission is not secure!

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So far mlb and tfl look promising even tho they'll require merging the initramfs.cpio.xz with the kernel into one file, thus complicating things.

[kkarhan]

OFC embedding the initramfs.cpio.xz is perfectly possible and if it should work with mlb and tfb...

[kkarhan]

blocked by:

• 5

• 6

• 7

• 8

as dependencies

[kkarhan]

FACT: the CORE version targets i486SX and up booting a 1.440 kB 3,5" FDD via BIOS/MBR, not UEFI/GPT !

[kkarhan]

Will have to see if mlb aka. Minimal Linux Bootloader or tfbaka. Tiny Floppy Bootloader will work and how much of a pain it is to do embed the initramfs.cpio.xz into the bzImage of the Kernel using CONFIG_INITRAMFS_SOURCE...

[kkarhan]

Considering the fact that the core Edition doesn't really do multi-user or multi-boot setups, the lack of multi-boot support is acceptable.

As for that - and support from being booted via USB I think refering to Ventoy as a easy-to-setup syslinux "distribution"...

After all, the big advantage of OS/1337 is that at it's current form it's entirely run from RAM after being loaded, which makes it a really nifty option already.

[kkarhan]

I've asked the maintainer of mlb if they were interested in adding initramfs support to their bootloader...

[landley]

In theory you can point CONFIG_INITRAMFS_SOURCE="/path/to/file.cpio.xz" and it will use it directly. But note that it cares about the name: it has to have .cpio in it, and if it's not .cpio.something it will try to compress it again. See usr/Makefile in the kernel source, line 30 or so.

[kkarhan]

@landley thanks for the hint.

And yes, you are correct down to the line...

I've to take a closer look then...

[kkarhan]

Integrating the initramfs into the Kernel at build time will be required.

Meaning that all the userspace tools including toybox must be built and integrated into the initramfs.cpio.xz before building the kernel...

That will require changing the build order as per Build Scripts...

[kkarhan]

I backed up mlb by forking it....

[kkarhan]

At worst I could just statically pull the release I made tho that would be a an ugly hack.

[sweetaibelle]

A few notes: In build.sh, ./pkgs/make-minimal-filesystem.sh actually creates the working directory that most of the other scripts use, so should be called first. You're also calling ./pkgs/make-mlb.sh in build.sh, but the actual filename is ./pkgs/build-mlb.sh (I also think that I'm calling sudo in a lot of places I shouldn't be, but given the scripts are broken at the moment, couldn't really test...)

[sweetaibelle]

Check the sb-dev branch which I think is most of the way there, with mldinstall actually building, though it's not being called with the right arguments.

[kkarhan]

yeah, I've to fix that...

[kkarhan]

I guess with the switchover to mlb should fix most, tho I did encounter an issue with that so I guess something with the initramfs.cpio.xz file went wrong as it's shown to be 1,6kB, which can't be right...