' BEE BASIC emulation in the browser(local)/on the desktop

[someone]

...I've learnt a lot about bank switching the past 24hours.

In someone's opinion the manuals don't explain it well.
Someone treats the DRAM on a 128K machine as four 32K banks (0-3).
All banks can appear at the memory map at 0000-7FFF and are selected by using the nominated bank select register bits (output port).
Bank #0 is the only bank that can also be at address range 8000-FFFF.
The other options such as VDU address, and ROM option bits are used to punch little holes into the DRAM (Bank #0) at address range 8000-FFFF.