If you want read-only memory today, you might be tempted to use flash memory or, if you want old-school, maybe an EPROM. But there was a time when that wasn’t feasible. [Igor Brichkov] shows … ...

Read-only memory (ROM) makes sure our computers and smartphones know how to boot up. Random access memory (RAM), lets us run programs on those computers. In the past, that's all we've needed.