On Fri, 08 Dec 2017 16:18:02 +0000, Mark J wrote:

>I started computing (literally : to compute) in about 1980,
> which says it all...
>
Noted. I started with mainframes in 1968, when what we now call a
'partition' was known as a 'diskfile' and allocated and initialised with
programs that were equivalent to a partition editor, e.g. parted, and a
formatter, e.g. mke2fs. As a concession to programmers, you could store
program source in 'subfiles' withing a 'diskfile'

> Nothing to backup yet, so no, and nothing put at risk.
>
Good news.

>> Deleting the boot partition means that the RPi is probably no longer
>> bootable.
>
> Did I write that? Must have, but I didn't mean to. My understanding is
> that if you change the start sector then the directory contents are
> effectively deleted. This is where I perceive gparted is not so
> transparent, and why I've left partitions well alone...
>
Yes. If you delete a partition and then create a new partition starting
at the same sector and with exactly the same size you may be able to
access the data therein because IIRC within a partition sectors tend to
be numbered from the partition start.

> I have, yet again, gone back to basics. The RaspberryPi.org website
> makes mention of zip and xz, and dd and ddescue, and writing to an
> sdcard,but no mention of any custom install or resizing /Boot.
>
Again, no comment as I've not tried to run anything but Raspbian on my
RPi, an early 522MB PI model B.

> This is where I read somewhere that DOS has a problem with writing files
> greater than 4GB, which is why I migrated to xz to dd via pipe, but I'm
> not using Windows, so can't see this is part of the problem, but piping
> avoids an intermediate step.
>
Yes, that's a limitation of the FAT filesystem. FAT16 partitions are
limited to 2 GB with FAT32 increasing that the 4GB and allowing filenames
longer than the original DOS 8.3 filename.

> Back to this new installation: Running it in the RPi3B gives a window
> saying that Root is being resized, and a reboot will happen in 5
> seconds. Then:
>
>  - the usual four raspberries, and text with "OK"s, save for the first
> line warning that a load module has not been loaded, or words to that
> effect, but this has always happened to no deleterious effect on
> different installations, and the installation progresses as usual.
>
> Disc Utility now shows /Boot as before, at 66MB FAT and the Root
> partition as 31GB ext4.
>
> /Boot now has 21.8MB used, 44.2MB free, and is Bootable
>
I can't help further with this: never used an RPi 3 or any flavour of
Ubuntu apart from once installing Mint on my sister's laptop. Apart from
my RPi model B all my computers are running RedHat Fedora.

One or two generic tips that may help:

- the 'man' command shows usually extensive help for using a program or
  library function, e.g. "man parted"

- the 'apropos' command lists programs whose manpage has the search
  term in its one-line summary description, e.g. "apropos ext4" lists
  tools for formatting and maintaining Linux EXT4 partitions. EXT4 is
  a journalling filing system, so is fairly resilient when dealing with
  power failures and system crashes.

- bookmark http://www.debian.org/doc/manuals/debian-reference/
  This is an main Debian reference manual, so is relevant to both
  Raspbian and Ubuntu. It can be quite technical, but there's very little
  that you might want to know that isn't covered.

- Since you other OSen, you may find a copy of "Linux in a Nutshell"
  would be a useful book to buy.

- you may also find "The RaspberryPi User Guide" worth a glance, though
  its may be more noobish than you want.

> mark@RPi3B:~$ sudo parted [sudo] password for mark:
> GNU Parted 3.2 Using /dev/sda Welcome to GNU Parted! Type 'help' to view
> a list of commands. (parted) quit
>
Should have typed 'print' to see the list of partitions before typing
'quit'.

> mark@RPi3B:~$ df -h Filesystem      Size  Used Avail Use% Mounted on
> /dev/root        29G  3.6G   25G  13% /
> devtmpfs        459M     0  459M   0% /dev tmpfs           463M  272K
> 463M   1% /dev/shm tmpfs           463M  6.8M  457M   2% /run tmpfs
>      5.0M  4.0K  5.0M   1% /run/lock tmpfs           463M     0  463M
> 0% /sys/fs/cgroup /dev/mmcblk0p1   63M   21M   43M  34% /boot tmpfs
>       93M   24K   93M   1% /run/user/1000
>
That looks pretty similar to what I see from Raspbian except that my
/dev/root is 7.2 GB with 3.1 GB used.

> Attempting to update fails because there are 512MB to be downloaded,
> which "needs 48.2MB on /Boot" so "please free at least 4063KB on /Boot"
>
> Case rests: why should a Distro fail to update a new install because it
> makes /Boot too small?
>
Pass. If nobody on here chips in, try asking on one of the forums at
www.raspberrypi.org or on a forum dedicated to Ubuntu on ARM chips if
there is one.

Sorry that I can't say any more, but it would be speculation if I did.


--
Martin    | martin at
Gregorie  | gregorie
          | dot org

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