[monocasa]

Or diode matrix ROMs were pretty popular as well.

Electrically, essentially what happens in most mask ROMs, but as a circuit board that allowed you to solder in a diode or not in each bit location in order to specify a 1 or a 0.

[cdcarter]

That would be the "hardwired" option.

[monocasa]

Eh, it was considered user programmable and generally came blank from the vendor.