I have just committed Guide Program 3 (and its associated samples
directory) to the SATK repository.
Program 3 is another version of Hello World. The big difference from
the previous two programs is that the message is delivered using I/O.
The program is a bit more complex and there is a lot more explanation
of how the program works to go along with it.
How the IPL channel program operates is also described in Program 3,
One of the challenges I have had in writing documentation is describing
how channel I/O operates. I am thinking that a description for
programmers, as opposed to a description for hardware engineers, might
be appropriate. Let me know what you think, please.