Its a VM
The VM is written in a subset of Smalltalk called Slang. This makes it really easy to debug the VM - because the debugging tools in Smalltalk are second to none.
There is a translator that tranlates this into C. The C makes very few assumptions about the underlying OS. A few glue routines need to be written to get mouse, keys, blit bits, network, time functions, file IO. Starting from zero, it takes about a week to create a new VM for a new platform. Fortunately for you, windows is already done (as is classic Mac, OS X, Linux, the commercial unices, and some palm tops).
The VM is launched with an "image" file. The image is basically a dump of memory. There is also a sources file and changes file that squeak needs for development. All code changes are logged.
You can file in or file out code from the image. But the image is a sort of garden of live objects. You don't so much write programs as put objects together and they just are. They live in the image. Saving the image is snapshotting your machine. You can have as many images as you like.
This isn't a good way to get a job. Not directly. While Smalltalk is by far the superior language and the source of most new ideas in software (extreme programming, JUnit testing, model view controller...) were invented in Smalltalk first, then ported to the weaker languages, Smalltalk work is scarce.
OTOH, its the best environment I know of. Crank through the free books. It will bend your mind.
I think that it's extraordinarily important that we in computer science keep fun in computing. When it started out, it was an awful lot of fun. Of course, the paying customer got shafted every now and then, and after a while we began to take their complaints seriously. We began to feel as if we really were responsible for the successful, error-free perfect use of these machines. I don't think we are. I think we're responsible for stretching them, setting them off in new directions, and keeping fun in the house. I hope the field of computer science never loses its sense of fun. Above all, I hope we don't become missionaries. Don't feel as if you're Bible salesmen. The world has too many of those already. What you know about computing other people will learn. Don't feel as if the key to successful computing is only in your hands. What's in your hands, I think and hope, is intelligence: the ability to see the machine as more than when you were first led up to it, that you can make it more.
--Alan Perlis
