… They're referring to the shelf launch date. I wasn't so attuned to Apple's announcements and launch dates then, but I remember its aesthetic warming past the horizon of my mind, with its plastic-looking stripes and bulbousnesses. The design seemed to match the tones and materials of the first iMacs, whose beigeless and rectangle-less appearance, considered Jony Ive's big splash, would signify that Apple was back. At least, that's what Steve Jobs seemed to hope, and this statement was more than skin-deep: he'd brought NeXT software into the picture, and this would serve as the foundation of Mac OS X, later known as OS X, later known as macOS.

The resolution of the first monitor on which I viewed my own installation, I think, was either 640 by 480 or 800 by 600. It was still the age in which one could easily see the pixels, and if I focused and squinted, I could make out the red, green and blue elements. There was no escaping the feeling that everything boiled down to horizontal and vertical lines, rectangles and squares, and that was a comforting and familiar feeling. It felt harmonious with Mac OS 9 and everything before, where bitmap fonts thrived and anti-aliasing seemed a more theoretical concept. Now, throughout this plasticky paradigm, I was seeing smoothed fonts, soft round buttons, and window edges that seemed to blur into each other. A minimized window would squeeze itself down into the dock like a pair of hands contouring an exaggerated hourglass figure on a mannequin, with no trace of pixellation. I wouldn't have called myself a fluent programmer then, but I could tell something fundamentally different was happening on a technical level. That would have been obvious anyway: apps like Adobe Premiere couldn't even run on Mac OS X – at least, not natively. Booting an app in "classic mode," one of my first tastes of emulation, temporarily plopped its pixellated countenance right into this blearier-looking world.

I've since learned about what was happening technically: terms like "object-oriented," "protected memory," "preemptive multitasking," and "UNIX-based" have unmasked themselves as sources of delight and wonder. Systems can crash, data can be corrupted, and programming takes ages, but these were ways around those, real treatments for causes rather than symptoms, things that would excite you if this was your life.

Steve had said on stage that Mac OS X would set Apple up "for the next 20 years," and he turned out to have understated. I'm not sure how much proverbial DNA today's version shares with the one launched on that day; it might be like comparing Homo sapiens to Homo erectus. The plastickiness is long gone, and the iMacs they imitate – while still in use here and there – feel more like relics than modern products. But those aforementioned concepts have stayed right at the heart of the system, having seen it across 17 major releases and three different companies' processor architectures. No sign it's about to end.

(Oh, and Scott says hi.)