C on the AS400 over the years.

I've got a two-fingered grip on the question I'm asking so please coerce
some of pieces of the question if needed be to postulate an answer.
 
We wrote some C stuff back in the early 90s and I was involved in
writing a client server application. I wrote the client side in RPG and
the someone else wrote the server side. I'm a bit familiar with C but
since I did not actually write the server side I'm fuzzy on some
details.
 
I seem to recall that way back that C400 did not have good file reading
(perhaps stream processing) capabilities so we wrote that stuff in
something called System C.  I can find procedures that reference having
to do stuff that I don't think is being done in the code today. 
 
While trying to find the CL program to do the MAKE (LINK) I came across
one with this in it.
/* This procedure will link the XXXXX program using CRTSYSCPGM  */
 
I can not find a CRTSYSCPGM on the system.
 
I'm pretty sure that all the C code is ILE stuff today. Might I assume
that the following MAKE (LINK) program
is what is probably used today.
 
 /* This procedure will link the XXXXX program using CRTPGM  */
 
Steve Moland