Computer hardware fundamentals – identifying bus/slot standards used in AT-class systems Which of the following is NOT a type of expansion slot or bus design associated with IBM PC/AT–class architectures and their successors used to connect add-in cards?

Introduction / Context:
Expansion buses and slots are how desktop computers add capabilities such as graphics, storage controllers, and networking. IBM PC/AT–class systems and their descendants introduced multiple slot standards over time, while some acronyms in computing refer to components that are not buses at all. This question checks whether you can distinguish real bus/slot standards from unrelated hardware terms.

Given Data / Assumptions:

• The focus is on bus/slot designs historically used with IBM PC/AT–class machines and compatibles.
• Options mix true expansion interconnects with a non-bus semiconductor device term.
• Only one option is not a bus/slot standard.

Concept / Approach:
Bus/slot standards include ISA (Industry Standard Architecture), EISA (Extended ISA), PCI (Peripheral Component Interconnect), and portable-card formats such as PCMCIA (also called PC Card). PROM, by contrast, stands for Programmable Read-Only Memory, which is a type of non-volatile memory device, not a motherboard interconnect.

Step-by-Step Solution:
List known PC/AT family buses: ISA, EISA, PCI are all valid expansion buses.Recognize PCMCIA as an expansion card standard used mainly in laptops, still a true expansion interface.Identify PROM as memory silicon, not an interconnect. Therefore, it is not a bus/slot design.

Verification / Alternative check:
Motherboard manuals and hardware histories show physical slots labeled ISA/EISA/PCI. PROMs appear as chips, not as slots, and are programmed once to store firmware or data.

Why Other Options Are Wrong:

• ISA: 8/16-bit legacy bus used widely in AT systems.
• EISA: 32-bit extension of ISA used in high-end systems/servers.
• PCI: Popular local bus introduced in the 1990s, successor to ISA/EISA for many devices.
• PCMCIA: Laptop expansion card interface (Type I/II/III), still an expansion standard.

Common Pitfalls:
Confusing component acronyms (PROM, EPROM, EEPROM) with interconnects. Remember: buses are pathways and slots; memories are chips.

Final Answer:
PROM