Computer buses: IBM’s Micro Channel Architecture (MCA) specified which data-path widths?

Introduction / Context:
Understanding historical PC buses helps when supporting legacy equipment or studying for hardware certifications. IBM introduced Micro Channel Architecture (MCA) as a successor to ISA, with different electrical and configuration characteristics.

Given Data / Assumptions:

• MCA is being compared by its data width capability.
• Common bus widths historically include 8, 16, 32, and later 64 bits.
• We focus on IBM’s MCA specifications, not EISA or PCI.

Concept / Approach:

MCA boards and slots came in 16-bit and 32-bit varieties. The 32-bit flavor supported higher throughput and bus mastering, differentiating MCA from ISA (8/16-bit) and EISA (32-bit) in design and licensing. Therefore, the correct pair is 16 bit & 32 bit.

Step-by-Step Solution:

Verification / Alternative check:

IBM PS/2 technical references list MCA models and expansion cards with both 16-bit and 32-bit implementations, confirming the specification.

Why Other Options Are Wrong:

• 8 & 16: Matches ISA legacy, not MCA.
• 16 & 24: Not a common PC bus width pairing.
• 32 & 64: Matches later PCI derivatives, not MCA era.
• None of the above: Incorrect because 16 & 32 is correct.

Common Pitfalls:

Confusing MCA with EISA or PCI; assuming wider always means newer across all vendors without checking the bus family.

Final Answer:

16 bit & 32 bit