Installing an EIDE Drive on Older PCs To add an Enhanced IDE (EIDE) hard drive to a legacy system that lacks built-in support, which component would typically need to be upgraded or added?

Introduction / Context:
Enhanced IDE (EIDE) introduced larger capacity support and improved transfer modes. Early systems without native EIDE often rely on add-in hardware to provide the necessary interface and onboard BIOS for drive recognition.

Given Data / Assumptions:

• Legacy PC without integrated EIDE controller or with limited BIOS drive tables.
• An add-in controller can include its own BIOS extension to support larger drives.
• CPU upgrades are not a requirement simply to attach an EIDE drive.

Concept / Approach:

When the motherboard lacks EIDE capability, adding an IDE/EIDE controller card solves both the physical interface and the BIOS recognition issue. These cards typically include an option ROM that initializes the drive during POST, bypassing older system BIOS limitations.

Step-by-Step Solution:

Verification / Alternative check:

Controller BIOS banner during boot and OS-level detection confirm the solution. Drive overlay software was another workaround but less reliable than hardware controllers.

Why Other Options Are Wrong:

“RAM BIOS” is not a standard upgrade path. A 286 CPU is unrelated to the interface itself. Replacing the ISA motherboard is unnecessary if an add-in controller is available. “None of the above” is incorrect because a controller board is the right fix.

Common Pitfalls:

Forgetting to set PIO/DMA modes, mismatched jumpers, or mixing 40-wire and 80-wire cables improperly.

Final Answer:

Controller board