Exercise 2: Why the Acorn/ARM/6502 Connection Is Stronger Than Resemblance — Possible Solution
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THE REAL HISTORICAL CONNECTION
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Per this chapter's own explanation, Acorn Computers — the British
company behind the 6502-based BBC Micro — went on to design ARM, one
of the most successful real RISC architectures in computing history
(today running in the large majority of the world's smartphones).
ARM's own original designers, including Sophie Wilson and Steve
Furber, have PUBLICLY, DIRECTLY credited the 6502's efficient, minimal
design as an actual influence on ARM's earliest design philosophy.
This isn't a claim this course is making by comparing two chips side
by side in hindsight — it's a documented account from the people who
actually built ARM, describing their own real design influences.

WHY THIS IS STRONGER THAN "RESEMBLANCE" ALONE
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"Resemblance" is a claim this course itself constructs by comparing
the 6502's own measurable properties (instruction count, cycle
uniformity, load/store discipline) against RISC's later formal
definition, and noting the two line up. That kind of argument, while
genuinely evidence-based, still runs the same risk cpu8bit1-1's own
warn-box already named for the whole course: reading a coincidental
similarity into a designed relationship that was never actually
there.

The Acorn/ARM connection sidesteps that risk entirely, because it
isn't an inference this course is drawing from comparing properties —
it's a testimony from ARM's own designers about what actually
influenced their actual design decisions. Real people, who really
built ARM, have said the 6502 really shaped how they thought about
efficient CPU design. That turns "the 6502 looks like it previews
RISC" into "the 6502 is a documented, acknowledged input into the
actual invention of a real, dominant RISC architecture" — a causal,
historical claim rather than a structural comparison.

WHY THIS WORKS AS AN ANSWER
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It states the specific historical claim (Acorn built the BBC Micro on
the 6502, then designed ARM, and ARM's own designers credit the 6502
as an influence), and explains precisely why a documented causal
influence is stronger evidence than a structural resemblance this
course itself is constructing by comparison — the difference between
"this looks similar" and "this is a stated cause."