I find it interesting that most applications seem to use a small amount
of RAM but a lot of ROM.
When the 4004 was designed, it had the extra pins assigned to select
more banks of RAM instead of ROM.
By the 4040 time they added more ROM select controls.
I don't think I've ever seen all possible RAM banks used.
Also, you see most applications using 1702s instead of 4001
or 4308. I've never seen a 4308 in the wild.
Dwight