Back in the 1980s, we crawled through a small door behind a filing cabinet, and we live, now and forever, inside the head of Steve Jobs.

Just look around; there is scarcely an area of technology his vision has not shaped. The mouse, desktop publishing, graphical user interfaces, bitmapped paint programs, digital music, smart phones, CGI animation in movies, tablet computers. Dare I say, the World Wide Web (the first Web server was a NeXT cube.)

Look around: We see a world mediated by Steve Jobs' vision.

And so, although I'm saddened by his departure as CEO, and concerned for his health, I don't share the foreboding and angst of the hyperventilating tech commentators about the future of Apple.

I once heard Tizra's David Durand retell an aphorism about systems. "Let me design the architecture," he said, "And I care not who writes the code."

And beginning in 1984, Jobs specified the architecture for our entire technological ecosystem.

I can still recall vividly the day I touched a Mac for the first time. It was late in 1984, at Macy's in Herald Square in New York, and I remember standing there, drawing rectangles on the screen with the mouse, completely enraptured. For someone who had grown up with punched paper tape and TROFF on Dec-10s, this was certifiable magic.

Of course, it goes without saying that Jobs didn't invent the mouse (thank you, Doug Englebart) or even the bitmapped display (pace, Xerox PARC) but his genius was putting it all together in a package. An irresistible package; one that made the Macintosh more than a computer. (Data point: When my future wife went off to Wharton for her MBA, I bought her a Macintosh 512k instead of an engagement ring. We're still married, 24 years later.)

Steve Jobs, the insanely great visionary, laid the plinth course of modern computing, and everything since has built upon that foundation.

There is nothing more pervasive than the desktop. I have three machines in front of me right now: Windows, Mac, and Ubuntu linux, and all three sport windowed environments inarguably descended from that first Mac.

Sometimes, the visionaries must wander in the desert for a while. Jobs faced some real challenges in the late 80s, when he was forced out of Apple, but what resulted was a whole new step function in computing.

I was at the Educom conference in Pittsburgh in 1986 when Jobs introduced the NeXT machine, and I still recall his pitch line. "People want a 3M machine," he said. "One thousand pixels, one thousand floating point operations a second, and they want it for about a thousand dollars." He showed Pixar's debut film, "Luxo, Jr." and the audience of academics were left drooling.

After the plenary, Jobs had a reception for tech folks from universities, and I was there as the computer coordinator from NYU, so, for the only time in my life, I was close enough to watch Jobs in person. His famed "reality distortion field" is no concoction of the computer press; I saw it in action as he totally pwned a roomful of Ivy League IT directors. I didn't have enough juice to meet him, but I did get to spend an amazing half hour chatting with Dan'l Lewin, one of the NeXT executive suite.

Yes, I have a NeXT pizza box out in the garage. And while the device didn't appear to succeed, it added several key control points to the curve of technology: unix on the desktop, multitasking in protected memory, and optical drives.

His return to Apple in 1997 began the consolidation of his vision across the computing landscape. From the return of the all-in-one computer in the iMac and the restoration of core design principles with the iBook, Jobs went on from strength to strength.

Geeks like me had been ripping to mp3 for a couple of years, but the iPod made it work for everyone. Then iTunes wrapped an ecosystem around it. The introduction of the first modern operating system, OS X, brought all the ideas of the NeXT box to a consumer level. The iPhone reversed everything that was true about mobile phones and redefined the category. The App Store changed software development business models, literally overnight. And the iPad did what no other tech firm had been able to do in more than ten years: sell tablet computers that people actually liked. Okay, Angry Birds probably helped.

And I haven't even mentioned Pixar, or the way they have completely redefined the animated film. Or the second-order effect that "Stevenotes" have had on raising the game for corporate presentations.

But the flame that burns twice as bright burns half as long, as the god of biomechanics says. And you have burned so brightly, Steve.

In his letter to Apple's board, Jobs said, "I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple's CEO, I would be the first to let you know."

Yes, there is sadness in this. But I only have to look around to be reassured. There is now a whole generation that has grown up knowing nothing but the graceful, elegant interface of the computer seen through Steve's eyes. There is a rising cadre of visionaries who will stand on the ramparts of this spectacular digital edifice and reach even higher. Because they live, and look, and listen, and interact inside the mind of Jobs.

Oh, and one more thing...

You totally rock, Steve. Our best wishes, always.

Full disclosure: I own shares of Apple, and I ain't selling.