PC expansion buses – Can an EISA and an MCA device coexist in the same personal computer? Assume a standard desktop platform without custom bridge hardware.

Introduction / Context:
EISA (Extended ISA) and MCA (Micro Channel Architecture) were competing expansion bus standards from the late 1980s and early 1990s. Understanding their incompatibility is important for supporting legacy systems and for exam-oriented PC hardware knowledge.

Given Data / Assumptions:

• EISA and MCA were implemented on different families of motherboards.
• No special bridge or adapter is assumed.
• Goal is to determine whether one PC can natively host both device types.

Concept / Approach:

MCA (introduced by IBM for PS/2) is architecturally and mechanically distinct from ISA/EISA. EISA extended ISA while remaining backward compatible with ISA cards; MCA was not mechanically or electrically compatible with ISA or EISA. Therefore, mainstream PCs never supported both buses simultaneously on the same motherboard.

Step-by-Step Solution:

Verification / Alternative check:

Historical motherboard references and service manuals list EISA or MCA, rarely both. No standard BIOS or chipset provided mixed-bus capability in desktop systems of that era.

Why Other Options Are Wrong:

Claims about “BIOS bridging,” “dock-station support,” or “reduced speed” do not address electrical/mechanical incompatibilities. Such configurations were not commercially offered for PCs.

Common Pitfalls:

Confusing MCA with PCI or thinking EISA is simply “faster ISA” that can adapt to MCA slots—mechanical keys and signaling prevent that.

Final Answer:

False.