Wrapping It Up
At the introductory assembler programming level, we have none of the
requisite skills to say much about the remaining chapters.
Of necessity, we will be brief.
Chapter 11 - Machine-Check Handling
Chapter 12 - Operator Facilities
Chapter 13 - Input/Output Operations
Reader's Comment Form
As we discussed in the Interruptions section, Machine Checks are
a kind of interrupt. In a sense, machine checks are generated by
a failing hardware component in the hopes that enough of the hardware
still functions well enough to process the interruption.
Since we will run MVS under the Hercules emulator, Hercules is what will
provide the Operator Facilities. See the various HTML files
distributed with Hercules itself, especially the Operating Procedure
section of the hercinst.php page.
If you're using the Fish GUI on Windows, the Operator Facilities are available
in a GUI rather than the normal linemode commands. I don't run the
Fish GUI myself (since I run Hercules in Linux), so I can't really tell you
where you need to look for the instructions; Fish maintains a webpage
that probably has the answers, the URL should most likely be in the
hercules-390 group's Links page on Yahoo!.
It's worthwhile to glance through this quite short chapter, just so
you have an idea of what Hercules commands you might want to use
to perform some of these operator facility operations.
The S/370 I/O model is somewhat different than most other hardware
designs, and generally speaking offers high levels of performance
on real hardware.
In terms of a S/370 hardware education, you can really say you
"know" the S/370 until you've done I/O yourself. This tutorial will
most likely not go that far.
We listed the Appendices when we introduced POPs. They contain some
interesting things, including Appendix A which contains some instruction
use examples. The POPs explanation of an individual instruction should
always refer to an example when there is one.
Furthermore, Appendix A contains a Number Representation section that
beginning assembler programmers should carefully examine.
Just about everything else in the Appendices are reference material.
The Index is probably the most-used section of POPs. It's where you
turn when you're not quite sure where to start looking, or want to
find an exact page number for a subject.
This concludes our whirlwind tour of POPs. We haven't begun to do it
justice, but we have hopefully given you some insight into how it's
laid out and where things are discussed.
We now resume our examination of the IEFBR14 program, using some of
what we've learned about POPs.