Changes

Note 2: The 74LS138 splits the address space to four regions (which is total nonsense), the 74LS20 is then merging them back to a single region (which is undoing that nonsense). There seems to be no real reason for doing that - except maybe to avoid legal copyright problems (claiming something like "no Although the 74LS138 is rather useless in this isn't a unlicensed remake of Schneider's schematiccase, our schematic is doing total nonsensethe book from Paul Bauriedl contains further schematics, it's has absolutely nothing to do with Schneider's hardware")in which the 74LS138 does have some purpose.