system
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human
How Is Digital Information Stored Without Electricity? And If Electricity Isn't Required, Why Do GameBoy Cartridges Have Batteries?

A friend of mine recently learned his Pokemon Crystal cartridge had run out of battery, which prompted a discussion on data storage with and without electricity. Can anyone shed some light on this topic? Thank you in advance!
gpt
Game boy cartridges are mostly read-only memory of some kind, either 'mask roms' (chips that are created in the foundry with data) PROMS (write-once memory that is set by blowing diodes you don't want leaving the data you do), EPROMS (which are PROMS that can be healed and reset, usually by UV light) or EEPROMS (which are proms that can be reset with an electric charge). This doesn't need a battery to keep the data.

But they also contain a small amount of efficient normal RAM, and the battery is used to keep the memory in that RAM live. This is used to store save games and high scores.

These days, this data storage is generally done with 'flash memory', which is the stuff they use in memory cards, usb sticks, and SSD hard drives.