RTEMS source structure

[Salman]

I'm a bit confused regarding some areas of the RTEMS source structure.

Could someone give me a hand on this?

I cant understand cpukit/libblock properly,
IDE seems to be split between the following two,
what modules/functionalities are supported by each section?
cpukit/libblock
c/src/libchip

My impression of the following two are as follows.
cpukit/libcsupport - provides basic RTEMS and OS functionalities
cpukit/rtems - uses the above to provide RTEMS API
is that correct ?

Is the POSIX API considered as an additional layer (sitting on top of
RTEMS API) or does it directly interact with libcsupport, making it at
the same level as RTEMS API ???

am I correct in saying cpukit/sapi is simply a set of "shared processor
modules" among all target CPUs ?

finally, I am unable to distinguish between the following two !
could someone explain this as well.
cpukit/score
c/src/lib/libcpu

Thanks a lot for your time,

Salman