Re: F2FS On USB Sticks?

The Natural Philosopher <tnp@invalid.invalid> wrote:

On 22/03/2025 01:42, Computer Nerd Kev wrote:

rbowman <bowman@montana.com> wrote:

On Fri, 21 Mar 2025 19:11:40 +0000, The Natural Philosopher wrote:

My other usage is Raspberry Pi SD cards which are two partitions in IIRC
VFAT and EXT4

>
That may be inherited from Debian.  vfat is used for /boot/firmware or /
boot/efi for UEFI compatibility.

 
Not from Debian, but for the same reason that like UEFI, the RPi
firmware only has drivers for FAT (FAT32, or FAT16 works too,
I'm not sure if any new ones support exFAT).
 
To run in a tmpfs, I set up Linux on a FAT partition on an SD
card. No need for a separate EXT* partition if you're not mounting
any as / anyway.
 

Then what are you mounting as / ?

The tmpfs.

I don't understand Linux needs a root filesystem that accepts linux
permissions, VFAT does not

Yes, but it can hold a file containing the filesystem data which is
unpacked into RAM during start-up. In fact this is common behaviour
with initrd unpacked to RAM during kernel initialisation and
mounted as /, after which the kernel can set up the partition it
wants to use as / and chroot to that. That second partition can be
an ext4 filesystem such as RPi OS uses, or it can be a tmpfs or
ramdisk with contents unpacked from an archive on the FAT FS into
RAM by the init script in the initrd. Or / can even just stay in
the initrd forever (which is what happens in most distros if the
latter steps fail).

So a Linux file system is really optional. The only FS you _need_
for booting on RPi or UEFI is FAT, because that's what the firmware
can load the Linux kernel from.

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