Robin bought a surprise present for me in the form of a book
called "Just for Fun" by Linus Torvold. ISBN 0-06-662073-2
It is an very interesting autobiography. Linus and I had parallel
experiences in the early days (1975-1985) of personal computers.
We both started with assembly language 6502's and went on to 68000's
and then forced into Intel architecture kicking and screaming.
The difference was I was forty years old and he was 11.
This goes a long way to explaining the way I feel about several things.
I especially like Linus's analogy with physics at the end of
this excerpt.
Physics is of course what I use to make judgments
about what is likely to work and what is not likely to work
in the world of rotary engines and their installation in aircraft.
Paul Lamar
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"We were all babes in the Unix woods, with a course that was
being made up as we went along. But what was obvious from this
course was that there was a unique philosophy behind Unix. You
grasped this in the first hour of the course. The rest was explaining
the details.
What is special about Unix is the set of fundamental ideals
that it strives for. It is a clean and beautiful operating system. It
avoids special cases. Unix has the notion of processes-a process is
anything that does anything. Here's a simple example. In Unix the
shell command, which is what you type to gain entry into the oper-
ating system, is not built into the operating system, as with DOS.
It's just a task. Like any other task. It just happens that this task
reads from your keyboard and writes back to your monitor. Every-
thing that does something in Unix is a process. You also have files.
This simple design is what intrigued me, and most people,
about Unix (well, at least us geeks). Pretty much everything you do
in Unix is done with only six basic operations (called 'system
calls,' because they are the calls you make to the operating system
to do things for you). And you can build up pretty much every-
thing from those six basic system calls.
There's the notion of 'fork,' which is one of the fundamental
Unix operations. When a process does a fork, it creates a complete
copy of itself. That way, you have two copies that are the same. The
child copy most often ends up executing another process-replacing
itself with a new program. And that's the second basic operation.
Then you have four other basic system calls: open, close, read, and
write-all designed to access files. Those six system calls make up
the simple operations that comprise Unix.
Sure, there are tons of other system calls to fill in all the
details. But once you understand the six basic ones, you understand
Unix. Because one of the beauties of Unix is realizing that you
don't need to have complex interfaces to build up something
complex. You can build up any amount of complexity from the
interactions of simple things. What you do is create channels of
communication (called 'pipes' in Unix-speak) between simple
processes to create complex problem-solving.
An ugly system is one in which there are special interfaces
for everything you want to do. Unix is the opposite. It gives you
the building blocks that are sufficient for doing everything. That's
what having a clean design is all about.
It's the same thing with languages. The English language
has twenty-six letters and you can build up everything from those
letters. Or you have the Chinese language, in which you have one
letter for every single thing you can think of. In Chinese, you start
off with complexity, and you can combine complexity in limited
ways. It's also the Windows approach.
Unix, on the other hand, comes with a small-is-beautiful
philosophy. It has a small set of simple basic building blocks that
can be combined into something that allows for infinite complex-
ity of expression.
This, by the way, is also how physics works. You try and find
the fundamental rules that are supposed to be fairly simple. The
complexity comes from the many incredible interactions you get
from those simple rules, not from any inherent complexity of the
rules themselves."
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