[OE-core] libs transition /usr/lib -> /lib questions

[Mark Hatle]

On 1/6/12 10:04 AM, Chris Larson wrote:
> On Fri, Jan 6, 2012 at 8:59 AM, Mark Hatle<mark.hatle at windriver.com>  wrote:
>> On 1/6/12 4:34 AM, Koen Kooi wrote:
>>>
>>>
>>> Op 6 jan. 2012, om 11:09 heeft Martin Jansa het volgende geschreven:
>>>
>>>> FWIW today I've noticed that systemd is going other way around
>>>> http://www.freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
>>>
>>>
>>> And http://fedoraproject.org/wiki/Features/UsrMove
>>>
>>> I guess it's time to publish my angstrom branch doing that after the
>>> holidays :)
>>
>>
>> I respectfully disagree with both of the above URLs.
>>
>> The root partition is still very useful as a "small" set of applications and
>> libraries required for booting.
>>
>> Most systems these days contain a combined root and usr partition, which is
>> fine.  However, there are a lot of systems that I've worked on in the past
>> and I expect in the future that, root being a small R/O system is necessary.
>>
>> initramfs can solve some problems, but introduces other issues.  Many of the
>> systems I've worked on simple don't have enough flash to be able to store
>> the bootloader, kernel and an initramfs [as well as other system items
>> required by the devices].  In this case a base rootfs makes the most sense.
>
> In my opinion, what's proposed in the two links is a good thing even
> for embedded. Not that we'd use that structure necessarily, but
> removing the usr vs non-usr separation for binaries and libs is a good
> thing regardless. Putting /usr in the rootfs still would still work
> fine, or you could drop usr entirely and move everything to / the way
> micro does.

I'd prefer if someone wants to flatten the filesystem that they move everything 
to '/'.  This will still work in the case where we move libraries and binaries 
between '/' and '/usr' in the generic case.

This would support both the traditional filesystem split case as well as a more 
modern single filesystem case.  (We even have the ability, even though I doubt 
it's been tested, to change the base_bindir, base_sbindir, base_libdir to be 
/usr/bin, /usr/sbin, and /usr/lib* to automatically move the things into /usr if 
that is the system someone wants.)

--Mark