Booting multiple BSDs.

Weaver weaver at
Sat Nov 14 19:33:04 UTC 2020

On 14-11-2020 20:30, Polytropon wrote:
> On Fri, 13 Nov 2020 19:02:29 -0800, David Christensen wrote:
>> I am confident that there are several boot managers, likely one for each
>> of those four OS's, that can find multiple bootable OS drives/ slices/
>> partitions and allow you to boot the OS of your choice.
> First of all, it's important to understand the different stages
> of OS booting, as well as the previous stage, likely involving
> UEFI. In order to select (!) from multiple operating systems,
> certain things must be neatly prepared or nothing will work
> as intended.
> There is a nice write-up by Manish Jain that deals with multi-
> booting FreeBSD, Linux, and "Windows", but in case you do not
> want a "Windows", leave out the corresponding parts - it will
> work in a similar way with multiple BSDs or Linusi, Linuxens,
> or Linuxera. ;-)
> Document here:
> In case you do _not_ have UEFI (i. e., you're using BIOS-based
> systems), tools like Grub2 can be really helpful as boot manager.
> It's easy to configure.
>> But, my
>> experience is that keeping them all running is an exercise in "infinite
>> bug propagation"
> "Get the worst out of all worlds!" :-)
> It doesn't matter if you have a multi-OS setting based on
> bare metal or in VMs - each OS you run will require a certain
> amount of attention if you want to actually _use_ it for a
> specific purpose instead of just "booting it".
>> I would remove three of those drives and run one OS at a time.
> In ye olden times, when BIOS was the thing in PC world, some
> BIOS vendors had a drive management option integrated: You
> could simply logically switch off drives, so they were still
> powered on, but not detected anymore, so the only drive (and
> maybe the data exchange drive) active were recognized, and
> the OS was thinking it was the only one available. Go to BIOS,
> switch off disk 1, switch on disk 2, and reboot - a totally
> different OS boots, with no possibility to interfere (!) or
> to "repair" (!!!) other system's disk content.
> Today, you have PF12 boot selection. :-)

Thanks for that.

Harry Weaver.
⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system

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