🚀 go-pugleaf

From the recent discussion on CTCA's, I have the impression that you write a
program that specifies the (virtual on CMS) addresses of the coupled CTCA's as
channel device addresses and then tramsmits data from one to the other by means
of an I/O program similar to one you would write for a DASD (disk). Until I get
a chance to peruse the Guide, does someone care to confirm or contradict this
impression? Since I read that a CTCA creates a link between two processors (or
virtual processors on CMS), I thought that instructions like RDD (Read Direct),
WRD (Write Direct) and SIGP (Signal Processor) would be used in a CTCA program.
         While I'm here: My system is a 4381 VM/SP running CP & CMS version 5.
I have a System/370 Reference Summary, Fourth Edition, November 1976. Is it too
out-of-date to be reliable? I noticed it doesn't give channel commands for the
3800 type of PRT currently defined for my virtual machine, nor for the 3370 or
3380 DASD's.
         This last question pertains to CMS. I know that the CMS nucleus, whose
layout is described by the macro NUCON, occupies the low end of memory in the
virtual machine. In that case, where are the Fixed Storage Locations, beginning
with IPL PSW, IPL CCW1, IPL CCW2 etc., ending with the CPU extended logout area
at D'512, which are an essential part of the 360 and 370 architecture? How can
I examine or change this area in CMS? Does it differ from BC mode to EC mode?