> Since Pascal text reading and writing each require their own open file 
> descriptor, and the Linux ioctl for modem control needs the C generated 
> file descriptor, I was stumped; "What is the file descriptor?"

Just about all I/O is done this way programmatically (files, pipes, sockets,
and all else you can think). Streams, like "FILE *fp" type, have an integer
file-descriptor handle associated with them, and you can go back-and-forth
between the two if you so please.

> Luckily, I have (at least) 2 books, "The Design of the Unix Operating 
> System" by Maurice Bach and "The Linux Process Manager" by John 
> O'Gorman. It seems Unix inventors already thought of this situation. And 
> when you think about it, all the glop on your Linux box starts from one 
> process. Only an old Minnesota penguin would enjoy learning about user 
> file descriptor table vs. file table vs. inode table.

How do you like the first of those two books? I do not need to read anything
else right now, as my list is growing, but maybe this is a book I should have.

"init" is the process you have in mind here. In some computer architectures
and OS designs, this is not the case. Amiga comes to mind, which was a true
multi-tasking OS that had its kernel built-in to the hardware ("Kickstart" was
the name of that "BIOS-like thing). Much love for Amiga here.

"Learning" is not for "old people" but for everyone. I wish more of my friends
devoted the time to learn about things like this. I wish I had read more of
this when I was younger. Keep learning. And my recommendation to you is to pick
a C book and learn that and steer away from Pascal. Respect for Niklaus Wirth,
but really, really try to get yourself to a better and more versatile place.
My 2 euro-cents.

> Unix and Linux must now be regarded as "critical infrastructure." These 
> systems have outlasted cars, roofs, furnace. The available documentation 
> is extraordinary. Old can be very good.

Passed the test of time, and the test of Microsoft. In the 90s, everyone was
changing to Windows. Circa 2005 there was an emergence of Linux. Now users are
essentially OS agnostic in many ways, and this is in part due to the enormous
popularity and versatility of Linux (based on the Unix philosophy and design).

And I will say that Linux is far from "old" if you really want to be technical.
One of its biggest advantages is the eagerness with which developers around the
world --independent enthusiasts or company employees-- add new features to the
kernel and the GNU foundation of the OS. At present, it is galloping forward,
and as a result more incompatibilities appear, more patches are issued, and
the kernel management is harder and harder work for those at the top. But we
are all benefiting from this. I'd rather not go back to the old days; the
future is bright.

There is a "Hardcore Hackday" meetup that I recently attended. You should see
the diversity of geekiness that was there... and most of us were Linux/Unix
people. Fun times were had and I met two of the readers of this list.