Labeling micro-SD cards ?

NOOBS is a good easy starting point for a straightforward computer with nothing "clever" about the setup. But it is not very flexible.

I discovered this after I installed NOOBS and Raspbian on a 16 GB card and later wanted to move the filesystem onto a 32 GB card so I had a bigger "system drive". It was easy to copy the 16 GB card to a 32 GB card with Win32 Disk Imager or a similar tool. But partition-expansion tools would not work: no matter what I tried I still had a 16 GB partition on a 32 GB card with the other 16 GB unused. There was something about the way NOOBS creates partitions that did not allow the main system partition to be enlarged to use all the unallocated space.

So I started again, installing from scratch. I forget now why 16 GB wasn't enough disc space, given that most of the data on the Pi was being saved to an external spinning HDD which I mounted to a directory below /home/pi/.

Nonetheless, it does work - but I'm not saying it's the best way, just another string to your bow.

/mnt is the traditional parent directory for mount points of miscelleneous filesystems that don't have a more natural home within the hierarchy e.g. /usr or /home may well be mount points themselves. It's essentially an administrator's convention when filesystems are manually mounted.

A mount point in /media, /var or possibly a few other options are those automatically mounted by your desktop environment. Traditional Unix never automatically mounted anything, both because of potential security issues or simply because historically there have been plenty of other things you might do with removable media other than put an FS on it.

That's because the root partition is supplied by UUID on the command line (on a Pi 1 running Pi OS from about a week ago):

$ cat /proc/cmdline coherent_pool=1M snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 video=Composite-1:720x480@60i vc_mem.mem_base=0x1ec00000 vc_mem.mem_size=0x20000000 console=ttyAMA0,115200 console=tty1 root=PARTUUID=c5881c32-02 rootfstype=ext4 fsck.repair=yes rootwait

Because it's mounted by UUID rather than a device node, the path is nominally /dev/root but that isn't a device node that needs to exist.

However, separately the UUID can be resolved:

$ ls -l /dev/disk/by-partuuid/ total 0 lrwxrwxrwx 1 root root 15 Sep 22 01:36 c5881c32-01 -> ../../mmcblk0p1 lrwxrwxrwx 1 root root 15 Sep 22 01:35 c5881c32-02 -> ../../mmcblk0p2

Basically, I think this is because the bootloader (GPU etc) is selecting which partition to use as the rootfs and supplying it as a cmdline flag, rather than being set by device node in the Linux world.

Theo

Then its pointless labelling The desktop linux pdesnt do it...e,g.

$df -h

Filesystem Size Used Avail Use% Mounted on udev 3.8G 0 3.8G

Both sda1 and sda5 exist

ls -l /dev/disk/by-partuuid/ total 0 lrwxrwxrwx 1 root root 10 Oct 17 05:41 51cec085-01 -> ../../sdb1 lrwxrwxrwx 1 root root 10 Oct 17 05:41 b1aaf3a7-01 -> ../../sda1 lrwxrwxrwx 1 root root 10 Oct 17 05:41 b1aaf3a7-02 -> ../../sda2 lrwxrwxrwx 1 root root 10 Oct 17 05:41 b1aaf3a7-05 -> ../../sda5