Peter Seibel - Coders at Work - Reflections on the craft of programming

Ingalls:Because it gives you real separation. Alan’s latest phrase—which is appropriate, I think—is it should be like the Internet all the way down. We worry about where we have security and various sorts of security mechanisms in programs and there are all sorts of things wrong with them. But the Internet-style separation is a real layer that there’s no way around.

So why is message passing such a good thing? That’s the reason: it separates the inside from the outside, 100 percent. At least, done right it does. And there are other systems that have gone farther with this and I think we’ll see more in that space.

Seibel:So nothing good ever gets really lost. Are there ideas, from Smalltalk or anywhere else, that you wish had been adopted by the mainstream?

Ingalls:I don’t really have wishes for the mainstream—I have things I want to do or that I would like to be easy. My one wish for the mainstream, in the context of computer science, is that people would go back to first principles a little bit more about ways to leverage computing in the intellectual space.

We’ve gotten incredibly good with the programming systems and the languages we know. What if we were that good with logic programming? And had it integrated well? I think we would be doing extraordinarily more stuff in much more of a human-oriented space. It does go in the direction of artificial intelligence. You have to know that at some point we’re going to cross a threshold where computers will be doing a better job thinking about stuff than we do.

I wonder sometimes if we’re unconsciously holding that off. A lot of progress was made, up until 1980, in that area. And the computers are orders of magnitude faster and bigger now. On the latest computer I got, if I run the Smalltalk music synthesis, in Smalltalk, it can compute the radio signal for a radio station. This is hard for somebody who, at one point, could watch simple arithmetic being computed.

So you take that and put it against all sorts of possibilities in logic programming, in rule-based systems, and artificial intelligence, and you have to know there’s lots of progress to be made there. I would like to see the kind of thinking that led to the Lively Kernel—what is a kernel apart from the language and the user interface? What other kernels are there? What if you build a kernel around logic programming and what kinds of things can you do with that? I don’t think that people are playing around with, tinkering with that stuff enough. Because, Lord, the machines we have today—if you have a minor breakthrough there you could do incredible stuff.

Seibel:Smalltalk was originally envisioned as a platform for use in education, right?

Ingalls:It was envisioned as a language for kids—children of all ages—to use Alan’s original phrase. I think one of the things that helped that whole project, and it was a long-term project, was that it wasn’t like we were out to do the world’s best programming environment. We were out to build educational software, so a lot of the charter was more in the space of simplicity and modeling the real world.

Something about having this educational goal made it easy to keep inspiring the lower-level stuff to be as simple as possible. So there were lots of things we did that didn’t run as fast as you might like. The first Smalltalk-72 system was really slow—the second revision on it ran about 20, 25 times faster. But we had it running, by God, and we were able to use it with kids and learned a huge amount before even trying a second version.

We focused a lot on getting some cool graphics to work, bitmapped graphics, music, and putting it together in a fairly simple language. What we learned from that did actually make a seriously good language. So after Smalltalk-72, we did Smalltalk-76, which was essentially Smalltalk-80. And I saw that that could be a serious programming environment for the industry. There was some tension there with Alan because he wanted to not get scattered in that direction.

It wasn’t too much longer before he left Xerox, and so we pursued those separate paths. But that was because we had discovered some things. For instance, our turnaround time for making changes in the system from the beginning was seconds, and subsecond fairly soon. It was just totally alive. And that’s something which I, and a bunch of the other people, got a passion for. Let’s build a system that’s living like that. That’s what Smalltalk became. So that then became a new goal, which then spun Smalltalk-80 off. Squeak was a return to that, but with the doing-it-in-itself bit added.

Seibel:So you and Kay followed, as you say, separate paths. Did you become disenchanted with the original Smalltalk vision?

Ingalls:No, not at all. I’ve talked about my training as a physicist, and I think it’s in my nature to look at the world—how it works, how forces are, how the planets move, how the winds blow, and all that stuff—as asking questions about it and really being in touch with the phenomenon. In the physical world, at least, that’s easy. You can zero in and come away with an understanding of, “Yes, that’s how it works.”

In computers I think there’s the same kind of thing. You should be able, in a computing environment, to zero in on music and musical synthesis and sound and just understand how the whole thing works. It should be accessible. The same thing with graphics. It’s put together very much the same way. You’ve got atomic things, which are the various graphical effects, and then you’ve got structural things you put them together with. The same thing’s the case for numerical calculation.

When I take somebody new with Smalltalk, I’ll say, “What interests you, taking text apart? Playing with numbers? Looking at graphics? Or playing with music?” And then we start there and do a deep dive on that. It’s very much still a part of my passion, and I’m sure Alan’s too, to take people through some deep dive in a direction that they’re motivated about so they come away with what Alan calls powerful ideas—the “aha!” that lets you see this amazing variety is really a couple of small, general things at work.

You can see that in music. You can see it in graphics. You can see it in numbers and text manipulation. And it’s really exciting to me to make that available and accessible.

The Squeak environment is really a computer scientist’s environment. The eToys environment is a kids’ environment, but not as comprehensive as it could be, and I still feel there’s a thing we haven’t done out there, which would allow you equally intuitively to dive in and get a physical understanding of those powerful ideas.

I’m still as passionate about that as anything. Why I’m here doing this stuff—JavaScript and the browser—is that we’re getting pretty close to being able to put Squeak-like material on a web page that you can browse from any browser and interact with in some nice, self-revealing way. That’s part of this whole picture. I’m sure it’s going to change. Browsers are going to change. We’ll get other languages besides JavaScript, and I’m still totally in touch with Alan and his group, who are doing another take on this going deeper down and trying to solve some of these other things more seriously. But it’s absolutely still the same vision.

Seibel:You mention four disciplines: music, graphics, mathematics, and text. Those are about as old as humanity. Clearly there are powerful ideas there that are independent of computers—the computer just provides a way to explore them that might be hard without the computer. Is there also a set of interesting, powerful ideas inherent in the computer? Is programming or computer science another deep discipline—a fifth area—that we can only do now that we have computers?