I recently got gifted an old Commodore PET. It boots straight into BASIC, so anything you type can be a command or a program, but what’s even cooler is the way the console (they call it “monitor”) works. If you press “up”, rather than scrolling through past commands one by one like in Bash, DOS etc. the cursor simply goes up the screen. You can modify anything you see and hit return to commit. This can be a previous command, a line of code or even the contents of the system’s memory (!).

It’s a really interesting form of direct manipulation that I have only ever seen matched by “document” style interfaces like Matlab, R etc.

If anyone is interested, I’ll do a write up later with some videos or something.