Parallel vs serial in microcomputers: In standard parallel data transmission used by microcomputers (for example, legacy printer ports), how many bits are typically transmitted simultaneously?

Introduction / Context:
Parallel interfaces transfer multiple bits at the same time across several signal lines. Classic microcomputer peripherals—especially Centronics-style printer ports—used an 8-bit parallel data path, reflecting the byte-oriented architecture of most systems.

Given Data / Assumptions:

• We refer to the typical microcomputer parallel port (for example, Centronics/IEEE 1284).
• Focus is on the data lines, not including status/control lines.
• Byte-oriented data transfer was standard for printers and some other peripherals.

Concept / Approach:

A “byte-wide” bus means 8 dedicated data lines (D0–D7) carry one full byte in a single strobe. Additional lines handle handshaking and status. Therefore, the number of simultaneous data bits equals eight.

Step-by-Step Solution:

Verification / Alternative check:

Examine pinouts of Centronics/IEEE 1284 connectors which clearly denote eight data pins plus several control/status pins. Interface documentation confirms byte-wide operation.

Why Other Options Are Wrong:

a: 16-bit parallel buses exist (for example, certain internal buses) but are not the typical microcomputer parallel printer interface.

b: 9 is incorrect; confusion may arise from 9-pin serial connectors (DE-9 for RS-232).

d: 4-bit nibble modes are fallbacks for compatibility but not the standard full-speed parallel transfer mode.

e: Not applicable because 8 is standard.

Common Pitfalls:

Confusing serial connectors (DE-9) with parallel data width, or counting control lines as data lines. Also, IEEE 1284 has multiple modes, but the fundamental data path is byte-wide.

Final Answer:

8