Exercise 3: Why "Obsolete" Doesn't Fit Either Chip — Possible Solution ==================================================================== 6502 EVIDENCE ------------------------------ Per this chapter's own section, WDC (Western Design Center) — founded by Bill Mensch, one of the 6502's own original co-designers introduced back in cpu8bit1-2 — still actively designs, produces, and licenses modern 6502-family processor cores TODAY, not merely as a historical archive but as an ongoing commercial product line. A chip whose direct descendant is still being manufactured and licensed by the very company founded by one of its original designers is not accurately described as "obsolete" — it's a design that has remained commercially viable across decades. Z80 EVIDENCE ------------------------------ Per this chapter's own section, the Z80 itself remained in continuous commercial production for an extraordinarily long stretch — decades — before shifting primarily toward licensed IP cores rather than standalone physical chips. Continuing to be manufactured and sold, in some form, for that many consecutive years is itself direct evidence against "obsolete," which implies a design that stopped being useful or produced long ago. THE BROADER EVIDENCE FOR BOTH ------------------------------ This chapter also notes that both architectures have genuinely active modern hobbyist communities, building real homebrew computers, new games, and demos on real or faithfully compatible hardware right now — not simply studying or emulating them as closed historical topics. "Obsolete" would suggest these architectures are no longer manufactured, licensed, used, or actively built upon anywhere — and per this chapter's own evidence, all three of those things remain true of both chips. WHY THIS WORKS AS AN ANSWER ------------------------------ It cites one specific, concrete piece of evidence from the chapter for each architecture individually (WDC's ongoing 6502 core business; the Z80's own multi-decade continuous production run), and adds the shared modern-hobbyist evidence as further support, rather than asserting "they're both still used" without pointing to anything specific the chapter actually states.