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. > 4. other installs with strong project dependencies Dependencies can indeed get out of hand sometimes. 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. > 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. -- https://bitfolk.com/ -- No-nonsense VPS hosting
