Place Eprom in Its Actual Commercial Niche Before Eeprom

# Place EPROM in Its Actual Commercial Niche Before EEPROM

## 8. Where EPROM Actually Won Business, Despite the UV Limitation

EPROM's UV-erase limitation did not keep it out of the market — it simply defined where it could compete. The niche that fit perfectly was low-volume or pre-production firmware storage: a product's code was relatively fixed by the time of mass production, so the UV inconvenience only applied during development, not in the field. Original equipment manufacturers used EPROM heavily for early microcomputer BIOS and boot code, industrial controller firmware, and instrument calibration tables during the design and qualification phase, then often switched the same system to a cheaper, non-erasable mask-programmed ROM once the code was finalized for high-volume production — EPROM's erasability was valuable specifically during development, and a cost burden specifically in high-volume shipped product, since EPROM cells and their ceramic windowed packages cost noticeably more than a mask ROM's simple plastic package. This development-versus-production split, not a single uniform use case, is the actual shape of EPROM's commercial era.