¿How many types of chips for the BIOS exist?

2 types exist:

--Those of the type EEPROM: (Electrical Erasable and Programmable Read-Only Memory)
That it means, memory of just reading that I could erase and is more, can be programmed electrically.

--The EEPROM Flash ROM: these types of chips appear about the appearance of the model of processor Pentium, and they have the great advantage, of which Software can be updated by means of a program.

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