What is that? A person hanging from a rope? A rune for “WTF”?

It’s neither of those, but it has been appearing in the memory of millions of Amiga computers since the dawn of time, right below the visible screen.

You might have seen it before if you were a very bored teenager in 1992 and used your cool new Action Replay freezer cartridge to inspect the memory contents of a freshly powered-on Amiga 500. That’s a contrived example, of course, and totally not a core memory of mine.

Coppenheimer will show you the same thing in the memory inspector when you load up a Kickstart 1.3 ROM and set the width to 40 bytes:

The location might give you a hint already: That shape is a leftover of the Kickstart hand drawing process! To be precise, it’s the result of the last “fill” command. Here is what the Kickstart ROM is drawing in slow motion:

In the video, all blitter activities are highlighted, i. e. whenever a line is drawn or a a block of data is copied, filled, or inverted. The drawing process is really slow and takes its sweet time to complete: 40 frames in real time, 0.8 seconds! In fact, when I hacked up a modified Kickstart that replaced the slow drawing code, that changed the familiar disk-clicking rhythm as well! It went from click (blank screen) – nothing (still a blank screen while you go get a coffee) – click (Kickstart hand appears) to click-click, with a barely noticeable blank screen between the clicks.

So there you have it. The answer to a mystery that nobody asked for, and a really niche and nerdy T-shirt idea. But it was a welcome opportunity to squeeze a little blog post out of the ongoing Coppenheimer update; “slow-mo” mode while you see what the chips are doing will be one of the features.