On Wed, Mar 01, 2023 at 02:38:20PM -0500, Steve Litt wrote:

> >A definition of init could be useful here: That's the one program the
> >kernel knows about[*]. After the kernel finished
> >booting, it creates a process and executes the init program. [**]
>
> Thanks Rainer!
>
> I inserted your definition into my presentation and attributed it to
> you. The presentation already had several other definitions, and yours
> adds the fact that PID1 is the only program the kernel knows about.

There's a bit of an ambiguity here. "Program" can (and in varying
contexts, does) mean:

- an executable file (maybe including interpreted scripts)
- a process

The fact that the distinction matters in this particular context is
illuminated by initrd / initramfs booting, when there are multiple
*executables* during various life stages of the system that run as PID 1.

--
Ian