It is well worth understanding how these older computers worked. All the components were doing double or triple duty, so that together all the tasks like refre

It is well worth understanding how these older computers worked. All the components were doing double or triple duty, so that together all the tasks like refreshing memory, reading/writing memory, generating video, generating audio, and I/O worked. This involved interleaving bus access and similar "tricks". There are an excellent series of talks at CCC titled "The Ultimate X talk" [0] where you are shown exactly how. I recommend The Ultimate Acorn Archimedes Talk [1] which introduced the ARM chip, but also shows how shared bus access and optimisation was the core principle of performant designs at the time. [0] https://media.ccc.de/search/?q=the+ultimate+talk https://media.ccc.de/search/?q=the+ultimate+talk [1] https://media.ccc.de/v/36c3-10703-the_ultimate_acorn_archimedes_talk https://media.ccc.de/v/36c3-10703-the_ultimate_acorn_archime...