EEPROM BIOS refers to the Basic Input/Output System (BIOS) firmware stored on an EEPROM (Electrically Erasable Programmable Read-Only Memory) chip on a computer's motherboard.
To understand EEPROM BIOS, it helps to look at the two parts: BIOS and EEPROM.
What is BIOS?
The BIOS (Basic Input/Output System) is a type of firmware that is the first software to run when you turn on a computer. Its primary roles include:
- Initializing and testing the system hardware components (like CPU, memory, hard drives, graphics card).
- Loading the boot loader, which then starts the operating system.
- Providing a basic interface for configuring hardware settings.
Traditionally, BIOS was stored on Read-Only Memory (ROM) chips. However, ROM cannot be easily updated. As hardware evolved, the need to update the BIOS firmware became necessary to add support for new devices or fix bugs.
What is EEPROM?
According to the provided reference, EEPROM (Electrically Erasable Programmable Read-Only Memory) is:
- A user-alterable read-only memory (ROM). This means while it's designed for reading, its content can be changed by the user (or the system).
- It can be erased and reprogrammed (rewritten).
- This erasure and reprogramming is done by the application of a higher-than-normal voltage.
Unlike older programmable ROM types like EPROM (which required exposure to UV light to erase), EEPROM can be erased and rewritten electrically while still in the circuit.
Combining EEPROM and BIOS
When BIOS firmware is stored on an EEPROM chip, it gains the advantage of being electronically updatable. This means:
- The BIOS can be flashed or updated with a newer version without physically removing the chip from the motherboard.
- This update process typically involves running a software utility provided by the motherboard manufacturer, which applies the necessary "higher-than-normal voltage" to erase and rewrite the EEPROM.
Storing BIOS on EEPROM became standard for many years before the transition to newer flash memory technologies (which are often considered a type of EEPROM but with larger block sizes and faster operations).
Benefits of EEPROM BIOS
| Feature | Benefit |
|---|---|
| Electrically Erasable | Allows easy in-system updates. |
| Electrically Programmable | Firmware can be rewritten with new versions. |
| Non-volatile | Retains information when power is off. |
| User-alterable (with tools) | Can be updated to support new hardware or features. |
Using EEPROM for BIOS was a significant step forward, making motherboards more adaptable and prolonging their useful life by allowing firmware updates.
Example Use Cases:
- Adding support for newer CPUs or memory modules.
- Fixing compatibility issues with specific hardware devices.
- Improving system stability or performance.
- Updating security patches or adding new features like UEFI (Unified Extensible Firmware Interface), which often replaced older BIOS implementations and was also stored on similar flash memory chips.
In summary, EEPROM BIOS refers to the system's fundamental startup firmware residing on a memory chip that can be electronically updated, leveraging the unique rewrite capabilities of EEPROM technology.
