Most cartridge-based console systems did not have modchips produced for them. They usually implemented copy protection and regional lockout with game cartridges, both on hardware and software level. Converters or passthrough devices have been used to circumvent the restrictions, while flash memory devices (game backup devices) were widely adopted in later years to copy game media. Early in the transition from solid-state to optical media, CD-based console systems did not have regional market segmentation or copy protection measures due to the rarity and high cost of user-writable media at the time.