Hi. 
Now, you might see a bus, but I see 
computation everywhere. 
The engines on this bus are run by a 
computer. 
The driver's console has a computer 
telling them where to stop next, whether 
they are on time. 
The security system, the cameras and the 
microphones, are run by a computer. 
The display on the side is run by a 
computer. 
There's a bunch of computers making this 
bus run. 
That construction site is the new student 
center. 
Right now it looks like trucks and 
concrete. 
But there's a ton of computation behind 
that. 
The architects and engineers who came up 
with the diagrams for it, were all 
sitting at computer workstations, of 
course. 
The did simulations of the traffic 
patterns in the building to see how to 
layout the rooms so that it would work 
well. 
They did simulations of the light 
entering into the rooms to see how that 
would work and to use light effectively. 
When I get my coffee in the morning, 
there's computation there too. 
The cash register's a computer of course. 
The credit card machine's a computer. 
The credit card itself has a computer in 
it. 
My name is Gregor Kiczales and I'm really 
excited about this course in Systematic 
Program Design. 
Walk with me a bit and we'll talk about 
it some more. 
So now that I've had my coffee and we're 
in a quieter place. 
Let's talk a bit more about why you'd 
want to take this course, why you would 
want to learn to design programs. 
We've seen one reason. 
Computation's everywhere. 
And one of my goals with this class is 
for you to be able to understand the 
world around you a bit better by 
understanding how those programs might 
work inside. 
If you could program, you could write a 
program that goes out on eBay and 
collects information and displays it to 
you a way that you want to see it. 
You can analyze data from physics or bio 
or chemistry and present that in a way 
you want to see it. 
You could even write an iPhone app and 
make a lot of money. 
Artists design pieces of work and 
performances. 
Lawyers design strategies, coaches design 
season strategies and training 
strategies, writers design outlines for 
their book, all disciplines design. 
And any time you learn a design 
discipline, which is what we are going to 
learn in this class then you become a 
better designer in any other discipline 
that you might work. 
Sciences like physics and math describe 
the world. 
They come up with equations which 
describe what happens in the world. 
But with computation, you can actually 
make things happen. 
So you can make simulations of the real 
world happen and you can also make unreal 
worlds happen. 
It's the difference between what's called 
analytical models and computational 
models. 
Once you have a way of thinking about the 
world in terms of computation, it's 
going to fundamentally change the way you 
think about the whole world around you. 
And really, when this course is done, 
you'll never see the world the same 
again. 
When I learned how to program, we kind of 
had to learn by osmosis. 
They would show us good code and bad code 
and say write good code. 
But a lot has changed since then. 
For one thing, we have a lot if empirical 
evidence about what really good code is. 
For another thing, we have what are 
called design methods. 
Design methods show us how to produce 
good code. 
Michael Jackson, in particular, has done 
a lot of work on design methods. 
And this course is based partly on those 
design methods. 
I mean a different Michael Jackson, 
British, wears a tweed jacket, doesn't 
dance as well probably. 
What a design method does is that it 
systematizes the process of going from a 
poorly defined problem to a well 
structured solution. 
And it does that in two ways. 
First, it helps us break down the problem 
into pieces and the solution into pieces. 
Any process of designing a program will 
do that, but when you have a method, it 
breaks it down another way, which is it 
breaks it down into stages of the 
process. 
So what you end up with is kind of a 
cross-cutting decomposition of pieces of 
the solution and pieces of the process. 
And that, breaking it down both ways 
really gives us a very fine degree of 
granularity for tackling really hard 
problems. 
By the end of this course, you won't need 
this design method to write the programs 
we're going to write at the beginning. 
But because you have the design method, 
by the end of the course, you're going to 
be able to write some truly hard 
programs. 
Another point I want to make 'cuz I know 
some of you may be concerned about it is 
that you don't need to be good at math or 
science in order to be good at program 
design. 
There may be some specific programs where 
you need to know some math or science. 
But there's other specific programs where 
you're going to need to know about some 
other kind of domain knowledge. 
You don't need to be good at math or 
science to do the programming we're going 
to do in this class. 
Now, here's my last point about the 
course and this is really important. 
This is the kind of thing that you learn 
by doing. 
You don't learn by watching. 
So, what I want you to be sure to do, as 
we work through this, is after you see me 
work a problem, turn off the video and 
try to work it yourself. 
Or take the practice problems that we'll 
give you and work them from scratch 
without looking at the solution. 
If you just watch me do it, you won't 
learn how to really do it yourself. 
Nobody ever got to be very good at 
playing the violin by watching somebody 
else play the violin, and this is the 
same kind of thing. 
It's a learn by doing skill. 
I hope you enjoy the course. 
I'm really excited about it, the TAs are 
really excited about it. 
We hope you're going to get a lot out of 
it. 
And we look forward to hearing from you 
on the course forums about how things are 
going.