Yeah, those are a thing on old Sun workstations. They have a clock and they also store a small amount of data. https://www.sun3arc.org/FAQ/sun-nvram-hostid.faq

Yeah, those are a thing on old Sun workstations. They have a clock and they also store a small amount of data. https://www.sun3arc.org/FAQ/sun-nvram-hostid.faq.phtml https://www.sun3arc.org/FAQ/sun-nvram-hostid.faq.phtml I remember replacing one in the mid 1990s. The machine's ethernet address is stored on this chip, and I believe it's battery-backed RAM (not flash, EEPROM, etc.), so when the battery dies, the data on the chip is lost. When you install a new chip, you need to program in the ethernet address so the machine can get on the network. The proper thing to do is use the factory-assigned ethernet address to ensure that it is unique. But you can't get the address from the old chip. So, like many people, I just picked some random numbers. It worked.