Choosing between kernels at install-time
I am trying to put together a custom LiveCD.
Our software needs a realtime kernel, and there are four or more
candidate kernels that would be good choices for different categories
of users.
Specifically, from debian repos:
https://packages.debian.org/buster/linux-image-rt-686-pae
https://packages.debian.org/buster/linux-image-rt-amd64
And from our private repo:
linux-image-4.14.148-rtai-amd64.deb
linux-image-3.4-9-686-pae-dbg_3.4.55-3linuxcnc_i386.deb
Basically, two almost-mainstream preempt-rt kernels and two RTAI
kernels. We have given up on making a 4.x.x Kernel with RTAI and 32
bit, but we do have a very good and stable 3.4.9 RTAI 32 bit kernel.
So, ideally, one LiveCD would install one of the four kernels, then
install Buster, then install the appropriate version of our software.
The way our software is compiled / linked means that each kernel has a
specific package for the software. With RTAI much of the code is .ko
modules that can only work with the kernel they were compiled against.
The build/install system enforces the same with preempt-rt, though I
am not sure if that is strictly necessary (but I do know that at the
moment I don't know enough to change that)
So, one install ISO, four kernels, four similar but different software
.debs (we do have our own repository, that part we understand)
1) I am guessing that the live image can detect an obligate 32 bit
system and choose a kernel that way?
2) Is there a way to ask the user for a decision on RTAI / Preempt-RT?
For most users Preempt-RT is likely to be best (it is mandatory for
some hardware). But for many of our new users, averse to spending
money on hardware, the RTAI kernel might be best. (especially on old
hardware, where the 32-bit RTAI kernel is likely to be best)
2a) I haven't done the experiment yet: Does Buster even work with a
3.4.x kernel?
My questions are largely about what can and can not be done, and what
makes sense to do (otherwise I would be trying to glean the info from
the docs)
Maybe we just need to have an explanatory web page with 4 download
buttons for separate ISO files, except that the 32 / 64 bit question
might be hard for many of our users to answer. I speak from
experience, I had never even thought about using Linux until I found
that the package I now work on was available only on Linux. I was a
Mac user.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912
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