Back in the days before mask ROM (when invented?) we got core rope memories, or Little Old Ladies memories, which required lots of human labor to build.
Were there any kinds of ROMs which were suitable for mass production before Semiconductor ROM dominated (when?) the market?
PS: I don't think the 1959 PROM satisfies the requirement. It needed lots of standalone diodes and auto assembly was not a thing yet(though auto burning might be possible?).
There are some canidates of non-volatile memories listed below beyond TROS or CCROS, andplease don't hesitate to teach me their PROs and CONs or if there was any other means.
- ENIAC's Function Tables were resistor matrix ROM
- Plated wire memory
- Thin-film memory
- Twistor memory
- Bubble memory
- Magnetic stick memory
- Two channel punched tape
LINK: Historical price of ROM