Do /dev and /run reserve 16GB space each?

While checking my free space I noticed this:

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
dev              16G     0   16G   0% /dev
run              16G  1,9M   16G   1% /run
/dev/nvme1n1p2  198G  163G   26G  87% /

I see /dev and /run each have 16GB allocated to them. Is this really so? Is 32GB allocated to these two paths? Or is it allocated in memory? What do those two values actually mean?

I guess rather this. To the stretch of what I know, rather than created on disk, these are created as tmpfs in memory for speed. The amount should be half of that of RAM if I am not mistaken. With 16 GiB, I get:

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
dev             7.5G     0  7.5G   0% /dev
run             7.6G   18M  7.6G   1% /run
/dev/nvme0n1p4   50G   14G   36G  28% /

This machine has 4 Gib:

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
dev             1.8G     0  1.8G   0% /dev
run             1.8G  1.3M  1.8G   1% /run
/dev/sda2       450G  8.0G  419G   2% /

on Pinebook Pro

➤ df -h
Filesystem      Size  Used Avail Use% Mounted on
dev             1.9G     0  1.9G   0% /dev
run             1.9G  1.2M  1.9G   1% /run
/dev/mmcblk1p2  117G   16G   95G  15% /


Those are maximum sizes for those temporary tmpfs locations. The default is 50% of RAM.

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[ricklinux@eos-kde ~]$ df -h
Filesystem      Size  Used Avail Use% Mounted on
dev              16G     0   16G   0% /dev
run              16G  1.6M   16G   1% /run
/dev/sda2       466G  107G  359G  23% /
tmpfs            16G   66M   16G   1% /dev/shm
tmpfs           4.0M     0  4.0M   0% /sys/fs/cgroup
/dev/sda2       466G  107G  359G  23% /swap
/dev/sda2       466G  107G  359G  23% /home
/dev/sda2       466G  107G  359G  23% /var/cache/pacman/pkg
tmpfs            16G  7.2M   16G   1% /tmp
/dev/sda1       511M  836K  511M   1% /boot/efi
tmpfs           3.2G  104K  3.2G   1% /run/user/1000
[ricklinux@eos-kde ~]$