April, 28 2004

Here’s another draft post from the “Unseen Alan” archives. This one was originally dated Feb 3^rd, 2004. If I recall correctly, I never posted it because I was so overwhelmed that I was having trouble collecting my thoughts properly. Mind you, it had been a busy week.

If I ever get around to it, I’ll also blog about the simulator computers – a roomful of racked 8086, 80286 and 80386 processors for each simulator.

My friend Glenn works at Qantas, maintaining their Flight Simulators. Last Friday, he very kindly took me for a tour of their Sydney facilities. It was amazing.

The Big Lesson

The big lesson is that hand-piloting a 747 is tricky. This is because you are attempting to push 400 tons of metal around the sky by yanking on a three foot stick. I am not good at it.¹ I didn’t actually write off a plane, but in the real world my flights would have headlined the news for a week and re-ignited world fears over airline security. Passengers still in possession of their mental faculties may have complained, too.

For instance, here is a picture out the window of 767, showing a genuine 110-degree bank.

Graphics, Optics and Cockpit

Here is the view from the cockpit of a 747–400. This is on the main runway at Sydney airport. The new control tower is to the left, and the old one to the right.

The simulators have clever – and expensive – optics that give the view out the windows a genuine feel of depth. The optics make the view ‘feel’ real, despite the blocky, circa-1989 graphics.

Of course, the inside of the cockpit looks and feels real, since it is made of all-genuine airplane parts. A large part of the simulator system is devoted to fooling the avionics and instruments into thinking they are on a flying aircraft.

Movement

The other big ingredient in the realism recipe is the simlator’s physical movement.

The simulators – which look like Star Trek space shuttles – are mounted on hydraulic legs, standing in the centre of a three storey room. The legs have about six foot of movement in them, so they can make sim can move up and down, tilt, and twist.

I gave the motion system a good exercise. I got a good shudder going by spinning the plane sideways off the runway.² During several flights, my unusually aggressive style caused the motion safeties to cut out, leaving the simulator on a permanent tilt for the rest of the flight. Way too much fun.

Thoughts

As I mentioned before, I was shown around the sims by a technician. Glenn has never flown a 747, but he knows how to start one, taxi it, take off, fly it to a destination and land it. Granted, he may not know the finer points, or how to handle an emergency, but he can perform all the basics competently. Qantas has whole buildings full of simulator technians, all of whom can fly Jumbo Jets. I’m not sure where I’m going with this thought, but there’s a b-grade movie plot in here somewhere.

Links

• There are more and better pictures on this site.

• Anthony Hicks has video of a 747 simulator session.

¹ I made a ten bounce landing at Tullamarine. Apparently it was some kind of record.

² Don’t know if it was realistic. Never want to find out.

While building my blogging software, my test data has been all the entries I ever wrote. Amongst them all, I found five or six never-published drafts.

So while we’re waiting for the DNS for cardboard.nu to shake out, I am running a series that I think of as “Unseen Alan.” I’ve given these entries a grammatical tidy up, and re-written the most egregious ramblings, but the basic thoughts are unchanged.

Here’s one I wrote on 25 September, 2003. Note the embarrassing comment about Perl and Lisp. How in the world did I ever hold that view?

In a recent post, Charles points out that it takes a lot of (keyboard) typing to iterate over a list in Java, compared to the same piece of functionality Ruby, Perl, Python, Lisp, Smalltalk, OGNL and Haskell.

It would only be a fair comparison if these languages were suitable for large systems development.

At the time Java was created, Ruby, Perl, Python, Lisp, Smalltalk, OGNL and Haskell were either non-existent or suffered serious deficits as large-systems programming languages.¹ Back then, the in-vogue large-systems programming language was C++.

Update: It turns out that Smalltalk is the best ever language of all time, including future time. It is a better language than French, Classical Latin or Swahili. My apologies to anyone whose sense of reality this post may have previously offended. (True story: All the good guys ‘do’ Smalltalk. Gandalf used VisualWorks, the Hobbits were blessed with Enfin, and Aragorn wielded Digitalk. On the other hand, Saruman coded Java, the Oliphants were fueled by COBOL, and the language Orcs grunted to each other was C – except the Uruk Hai, who spoke ANSI C++.)

Java compares well to C++. As Phillip Pearson points out in the comments on Charles’ post, Java is an improvement over C++ for this task. Java is also well ahead of previous choices for large-systems programming: Assembler, COBOL, Fortran and C.

These days, however, some of the comparison languages are becoming suitable for large-systems development. Python particulary interests me, but Perl is developing in a promising manner and there is a slim, but frightening, chance that Lisp Smalltalk may yet gather a critical mass.

¹ I snort in the direction of the OGNL-Java comparison. OGNL is neat, but it cannot replace Java.