RSB: Why is "/usr" the default prefix?

[Sebastian Huber]

----- Am 11. Jan 2019 um 15:38 schrieb Sebastian Huber sebastian.huber at embedded-brains.de:

> Hello,
> 
> why is "/usr" the default prefix? RTEMS does not belong to the host system. I
> think it should be "/opt"
> 
> http://refspecs.linuxbase.org/FHS_3.0/fhs/ch03s13.html#purpose14
> 
> or "/usr/local"
> 
> http://refspecs.linuxbase.org/FHS_3.0/fhs/ch04s09.html#purpose24

Sorry, I mean why is it "/usr" on Linux.

Another question, the user manual says in the prefixes section:

"A further reason not to use the standard prefix is to allow more than one version of RTEMS to exist on your host machine at a time. The autoconf and automake tools required by RTEMS are not versioned and vary between the various versions of RTEMS. If you use a single prefix such as the standard prefix there is a chance parts from a package of different versions may interact. This should not happen but it can."

I think this is quite inconvenient from RSB to use such a prefix. Why can't it use OS standard prefix (e.g. "/opt" or "/usr/local") + rtems + version, e.g. "/opt/rtems/5" by default? You still have the root permission problem, but the we get rid of the conflicting versions stuff.