You can more or less fully understand an entire 80s home computer. The CPU, the memory access, the peripherals, and the graphics subsystem (…if you can call it

You can more or less fully understand an entire 80s home computer. The CPU, the memory access, the peripherals, and the graphics subsystem (…if you can call it that). Operating systems were simple by modern comparisons. Hardware is relatively cheap, and emulators at reliable, there was also a wealth of shareware available for many use cases, now much more easily available than when I ran a public access BBS for it.