Technical deep dives, programming tricks, ROM lore and other long-form pieces about the ZX Spectrum and how it really works.
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Every Spectrum program you've ever typed says OUT 254 or IN 254. The ULA doesn't actually check for 254 — it barely checks anything at all. A tiny program proves it, live, on screen.
A single SCREEN$ file that displays a picture when loaded to the screen — and runs as Z80 machine code when loaded anywhere else. The code is literally visible as colours.