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Light Pens and Pocket Protectors Part 3

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A history of computing

Let’s jump back in time to the year 1961 for a moment. Back in 1961 there was this guy named Ivan Sutherland, who was a student at the Massachusetts Institute of Technology.

    Now even though I’ve never seen a picture of Ivan, I can see him clearly in my mind’s eye. There he was with his crew-cut hairdo, hunched over his slide rule, adjusting his black horned-rim glasses and, perhaps, fiddling with his pocket protector. Now Ivan might have looked like a nerd, but he was a nerd with a pretty good idea that would soon revolutionize the world of computing.

    It could have been Ivan was bored with school and just felt like doodling, (admit it, a lot of us would rather doodle than study), or he might have been looking for an idea for his Ph.D. thesis. But as he flashed a light pen across his primitive computer screen in squiggly patterns he was struck with an idea.

“Jeepers!” he exclaimed. “I will invent a way to draw a picture with a computer—and I will call this drawing program Sketchpad.”

    Well, maybe it didn’t really happen like that, but Sutherland was the first to demonstrate the principles that are now the basis for most computer graphics programs—and he did use them, and Sketchpad, for his 1963 M.I.T. Ph.D. thesis.

    The light pen was one popular means for computer researchers of that day to interact with their computers. The pen had a photoelectric sensor at its tip that emitted an electronic pulse back to the computer when it was struck by an impulse from the electron gun within the monitor. Since the electron gun zipped back and forth at specific intervals, it was a relatively simple matter to calculate where the light pen was on the screen by when the pulse hit it.

    Sutherland’s Sketchpad supported the manipulation of objects, via the light pen, which included grabbing objects, moving them, changing size and using constraints. Sketchpad’s graphics were read by the computer as mathematical vectors, which described their locations upon the screen by  grid coordinates.

    Later, others would develop another means of drawing on screen with what was to become known as raster, or bitmap graphics. With bitmap graphics, each pixel on the screen is assigned a value and is individually accounted for. Vector graphics were unable to represent a graduated value between light and dark within a solid form and, inversely, bitmaps were not able to clearly and efficiently render lines.

    In 1961 there was another M.I.T. student, Steve Russell, who was not only scientifically bent, but also had a playful spirit. Russell was the inventor of one of the first computer games, Spacewar. However, to give credit where credit is due, the true grandfather of computer gaming is probably William Higinbotham, a nuclear physicist who in 1958 used an oscilloscope and two crude controllers to entertain visitors at the Brookhaven National Laboratory in Upton, New York.

    Higinbotham called his game Tennis for Two, and probably kicked himself in his radiation-tainted butt for not patenting the idea. In the next few decades, video and computer games would become a multi-billion dollar industry. One of the earliest was called Pong—remember that one?

    Back in the land of personal computers, right around 1970, corporate America was beginning to wake up and hear the sound of money jingling in the new technologies. David Canfield Smith coined the term “icons” in his 1975 Stanford Ph.D. thesis and went on to become one of the chief designers at Xerox’s Palo Alto Research Center.

    The concept of the “WYSIWYG” or “what you see is what you get” computer interface originated at PARC. The first commercial computer systems to use icons, menus and a graphical interface (GUI) were made by Xerox in 1981, (the Xerox Star), which was followed in 1982 by the Apple Lisa and the first popular commercial computer to sport a GUI, the Apple Macintosh, in 1984.

    In the next installment of PC history, we’ll take a look at the tale of a mouse and the birth of windows, even before Bill Gates stole—uh—appropriated the idea.


    Ben Silverman is a writer from Sandpoint who makes no apologies for his dislike of the Microsoft “Empire.”

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Ben Silverman

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