This installs a full Smalltalk environment on a bare metal Rasp Pi. There’s a link to another version that runs Smalltalk 80 (GNU Smalltalk) in the OS in the article.
Today, you probably don’t think much about object-oriented programming, it’s just part of the landscape. But decades ago, it was strange and obscure technology. While there were several languages that led up to the current object-oriented tools we use today, one of the most influential was Xerox PARC’s Smalltalk language. [Michael Engel] took a C++ implementation of the Smalltalk VM, some byte code for a complete Smalltalk system, a Raspberry Pi “bare metal” library, and produced a Smalltalk workstation running on a bare Raspberry Pi — even a Pi Zero. The code is on GitHub and is admittedly a work in progress.
If you don’t want to use a spare flash card to boot into the system, there are Smalltalk 80 versions that run on normal operating systems. The tutorial in that program’s user manual might be helpful to you if you haven’t done Smalltalk before.