Not that it has anything to do with anything in this video, but if anyone is interested in what can be done using TTL logic and a lot of PROMs, please consider looking at Professor Matt Regan's KZfaq channel. Here's a link to his TTL based (i.e. *NO* 6502 micro, but lots of PROMs and a bit of TTL) Apple II system: < kzfaq.info/get/bejne/nt51eMmExt-2fqM.html >