On 08/19/2024 02:51 PM, Andy Smith wrote:
Hi,
I'm afraid I have not got the kind of answer you request for your
actual question but…
On Mon, Aug 19, 2024 at 06:19:26AM -0500, Richard Owlett wrote:
I'm over 80 and doing first "from scratch" install since Squeeze ;}
Hardware is Lenovo R61 ThinkPad (64 bit).
I multi boot [Grub will have at least three options]:
1. minimalist installation - primarily command line usage
2. 64 bit Debian with maximum features
3. 32 bit Debian - couple of applications require a 32 bit OS
All 32-bit x86 software runs on a 64-bit kernel no problem¹ on
Debian, so it's unlikely you actually need to dedicate a whole
install to a 32-bit kernel, which also as previously mentioned has a
single digit of years of remaining lifetime in Debian.
I don't see anything on https://wiki.debian.org/LTS that implies shorter
lifetime for i386 than anything else.
4. other installs with strong project dependencies
Dependencies can indeed get out of hand sometimes.
I wasn't speaking of "software dependencies". For different projects I
want different "working environments".
I don't know how much you are up for a learning experience but
virtual machines or containers can often be a good way to
compartmentalise projects and their dependencies without needing to
do whole separate installs.
So you see, I think your use case can be handled with only one
Debian install, using containers or VMs for the projects with a lot
of dependencies. But I appreciate it's a lot to get stuck into.
I looked into VMs long ago. For my style - no advantages worth the effort.
Today's question
At boot time, what determines which physical partition gets mounted as a
specific directory ( /, /home, swap, and so forth )?
You asked for pointers to complete documentation on this and I can't
do that which is why I said this wasn't going to be an answer to
your actual question.
A summary however is that:
The grub entry provides an initramfs and a device for use as root.
The initramfs provides a temporary root filesystem containing all of
the tools necessary to mount the actual root device as root.
It then mounts root (which must also contain /etc). If root did not
also contain /usr then that is also mounted at this point.
The real init from the root filesystem (systemd) then takes
over, looks at /etc/fstab and mounts everything² in there at the
places it says.
So, there are multiple things going on here as regards what gets
mounted where. The bootloader entry decides which device / will be
on (you can test this by changing / in the fstab — whatever is in
the bootloader entry will prevail). The initramfs can mount things
outside of the direction of fstab but tyoically doesn't. Then the
init system from the real root filesystem reads /etc/fstab.
Finally there can be systemd .mount units outside of fstab, but
again that is not typical and you'd know if you added those.
Thanks,
Andy
¹ By which I mean if it runs on a 32-bit kernel it will work on a
64-bit kernel as well unless they went out of their way to ensure
it won't work.
² Some things in /etc/fstab can be set to "noauto" to prevent them
being automatically mounted at boot time.
