Tubes, Condensers, Punch Cards And Magenetic Core Memory

In the late 1940s Dr. An Wang, and Jay Forrester, who was head of the Whirlwind computer project invented core memory at MIT. Magnetic core memory replaced vacuum tubes and mercury delay lines with a much more compact and reliable technology.

Core memory, or more accurately magnetic core memory is a random access memory (RAM) system that was developed at MIT by Jay Forrester in 1951. It was initially very expensive to fabricate but prices dropped as the market developed. it was used extensively in the 1950s and 1960s.

Whirlwind was MIT's first digital computer and the first digital computer built specifically for real-time control. IBM then licensed the technology and core memory became commonplace much of the first and second-generation of IBM computers. A young engineer named Ken Olson, founder of Digital Equipment Corporation, was heavily involved as the liaison between MIT and IBM.

In 1956, IBM paid Dr. Wang $500,000 for his patent on core memories, which he used to expand his company, Wang Laboratories.

Sketchpad And Analog Vector Display

About seven years latter another giant appeared and produced the first computer generated display while at MIT. Ivan Sutherland was working on his Ph.D. in 1963, where he had the great fortune of being selected to study under Claude Shannon, the inventor of information theory. Sutherland developed a computer program, called Sketchpad, that made it possible to create graphic images directly on a display screen by using a hand-held object such as a lightpen - but, it wasn't a digital display, it was a stroke or vector display, an analog display.

Analog operates (primarily) on a varying voltage. The best (easiest) example is a light dimmer. When you turn up the control you're increasing the voltage to the lamp and it gets brighter. In a vector display, as you increase the voltage on one side of the tube the spot on the screen will move toward that side, etc. That's the basic way a TV screen works, a voltage is varied up and then suddenly down in what is known as a sawtooth. The beam moves across the screen and then suddenly goes flying back. Each time it goes flying back (to the left), it's pulled down a bit too, thereby creating lines across the screen, 625 of them in Europe, 525 in the U.S. and Japan. It's an analog display designed in the late 1930s and still in use in every home in the world that has a TV.

When the first computers were built they too were analog. In 1930 Vannevar Bush (an ancestor of the U.S. presidents) invented the first analog computer. One of the first uses of a computer was to project the trajectory of cannons in WWII. Like so many things, analog computers were developed primarily for military applications. One of the most famous analog computer, albeit never built (except in a book by William Gibson and Bruce Sterling)) was Babbage's analytical engine (1839). Babbage theorized about the possibilities of such a machine but never believed it could actually be built, it was, "just too complicated."

However, vacuum tube amplifiers used mostly for audio could be built with great precision as far back as WWII (the vacuum tube was invented 1904) and would provide reliable, reproducible, results. A certain input voltage could be used as a bias and cause a different and predicable output voltage. The voltages could be thought of as numbers to some degree of accuracy (typically not much less than plus or minus one percent), but that was better than what could be obtained with a slide rule and much, much faster. But analog computers had a major problem, no significant memory capability to store partial answers, so digital, with core memory quickly won out.

However, it was with an analog vector display that Ivan Sutherland introduced the world to computer graphics. Like all great insights and ideas, Sutherland ignited the imagination of engineers, scientists, designers, and artists all over the world. And, as one might imagine, his concepts also excited the military as well. Although the medical profession didn't immediately see the applicability of computer graphics, and in fact didn't really embrace the technology until the 1980s, chemists were quick to recognize the potential of computer graphics as tool to model molecules.

The analog vector display, as well as the analog computers continued to be enhanced and got faster and more accurate every year, long before Intel's Dr. Gordon Moore was out of college. By the early sixties analog computers could computer with accuracies of one part in ten-thousand, an astounding accomplishment, and they were the scientific computer of the day for many special problems (like oil & gas reserve, and weather calculations.)

From Digital Switches To Transistors

But along the way Bell Labs again rocked the boat and introduced a semiconductor amplifier. Amplifiers can operate as a class A, meaning perfectly linear, or as a class C, which flips from one state (zero volts out) to the other (max volts out) with a slight variation of the input. Although annoying to folks who wanted a nice clean output signal, these class C amplifiers could be used as a switch, passing an amplified amount of current or voltage, from a much smaller input signal. So they found their way into industrial controls for motors and lights and solenoids. Digital switches were waiting to be discovered.

Bardeen, Shockley and Brattain, scientists at Bell Laboratories were actually was performing experiments as early as 1947 that lead to the invention of the transistor. (There's a philosophic argument about such things: are they invented or just discovered since they operate under the laws of physics. The question has interesting logical extensions with regard to patents.) In any case, when the researchers came to the discovery of the bandgap principle they were seeking to develop a better, smaller, lower power amplifier. But they weren't, initially, very good amplifiers, operating only as a class C switch. That problem was quickly figured out and soon we had commercial transistors that could be used in hearing aids and radios.

The first transistor radio was built in 1954 (using TI transistors even though Raytheon was the first to commercialized them). When Thomas Watson saw one he bought a box of them, gave them to his top engineers and told them to put transistors in to their computers. (TI made a small fortune supplying IBM with transistors over the years.) So IBM gets credit with developing the first transistorized computer.

They would have never made any impression on anyone if they had to be programmed with Hollerith code or the basic code of the registers known as assemble code. No one was more aware of that than the military who wanted those giant calculators for obvious reasons to be more deployable and easier to use.

Although Mr. Watson never said it, he felt their pain. And so he instructed his army of engineers to come up with something, and they did, FORmula TRANslation-FORTRAN, thefirst high level programming language. One of the key inventors, John Backus (who was then 29 and a mathematician at Columbia University) said he was inspired to develop Fortran after he had spent several years working on IBM's 701 and 704 computers and was simply tired of the complexity of programming. In late 1953, Backus wrote a memo asserting that at least half to three-quarters of the operating costs of a computer were from programming and testing. (Things aren't much different today.) In 1954 he got the go ahead and developed the tool that allowed the exploitation of the new built-in floating-point co-processing and index registers in the 704. Computer graphics is built on floating point more than anything else.

The transistor was igniting the imagination of lots people, not just those building radios and computers and in 1957, Sherman Mills Fairchild, founder of Fairchild Camera and Instrument Corporation, sponsored a small group of young scientists in California in their development of a new process for the manufacture of transistors. The goal of those Fairchild scientists - among them Robert Noyce and Gordon Moore, eventual founders of Intel Corporation - was to develop, mass produce and market semiconductors. They reached the goal in 1959 with the introduction of the Planar process. Planar technology became the fundamental method of producing transistors and integrated circuits and is still regarded as one of the most significant achievements in semiconductor technology since the invention of the transistor.

So by the early sixties almost all the pieces were together. We had solid state digital computers with floating-point capability, which had bigger magnetic core memories, and we had an easy to use and powerful programming language. We also had Dr. Shannon and his protégée Ivan Sutherland. The stage was set; computer graphics was ready to happen.

And it did happen. Although we take these abilities very much for granted today, Sketchpad was the first program that allowed the creation of graphic images directly on a display screen rather than by entering codes and formulas into the computer through a keyboard. Even more revolutionary, it allowed for the information that was stored in the computer to be altered and updated by changing something on the display screen. For the first time, it seemed possible that computers could be used for something other than data processing. Sketchpad's abilities opened up the new field of computer-aided design, which became known as CAD and is still used today.

But the display was an analog display.

Raster-Scan Displays

The analog display stayed the workhorse of the computer industry up until the early 1980s. Big 27" round displays with perfectly flat faces where used in CAD systems (where designers would actually take measurements off the screens), in air-traffic control systems (many of them still in use today around the world), and in early warning missile systems.

In the commercial and scientific sector Tektronix became the dominant supplier of such displays and added another feature, storage in the tube. By carefully and cleverly recharging the phosphor screen and image could be maintained on it forever. The Tektronix storage tube was the computer graphics display, and remarkably Tek had very few competitors.

Tektronix was started in 1946 during the electronics revolution that took hold after World War II. The company's founders developed a way to accurately measure and display high-speed electrical signals on a device that became known as an oscilloscope.

In the late 1960s and early 1970s companies began experimenting with raster-scan displays for computer graphics. Raster scan, the TV scanning technique, had been used in the sixties for monochromatic text display for time-sharing terminals and computer consoles. They had a small amount of memory, about enough for one character, and turned on and off the beam as it scanned across the face of the tube. This produced a series of dots (exactly like a dot-matrix printer) that could be seen as characters based on the ASCII code.

The ASCII code was originally developed for teletypewriters but eventually found wide application in personal computers. The 7 bit ASCII (American Standard Code for Information Interchange) is the heart of all computer codes and even HTML even though it only supports 128 characters.

ASCII was created in the early 1960s but didn't become a U.S. government standard until 1968. In the 1960s, there were many data communication codes that were competing for the US Standard. In 1962, IBM had created and promoted Extended Binary-Coded-Decimal Interchange Code (EBCDIC). This is an 8 bit code, which allows up to 256 characters. However it lost out to ASCII as a "PC standard." EBCDIC is still used on many mainframe systems even today.

SpaceWar!

Commercially available computers were available from several companies by the 1960s, although its estimated IBM had over 80-percent of the market at the time. In 1960 the precursor to the minicomputer, DEC's PDP-1 sold for $120,000, included a CRT (cathode ray tube) graphic display, needed no air conditioning, and required only one operator. It's large scope CRT intrigued early hackers at MIT, who wrote the first computerized video game, SpaceWar!, for it. The SpaceWar! creators then used the game as a standard demonstration on all 50 computers. Dueling players fired at each other's spaceships and used early versions of joysticks to manipulate away from the central gravitational force of a sun as well as from the enemy ship. It was for me the most exciting thing I had ever seen.

During this time transistors were getting better and had taken over computers completely. Fairchild Camera and Instrument was leading the industry with a series of firsts quickly followed by Texas Instruments. In 1967 Fairchild built the first standard MOS (metal oxide semiconductors) for data processing applications, an eight-bit arithmetic unit and accumulator, and in 1968 Burroughs produced the first computers (B2500 and B3500) to use those integrated circuits. But they were still using oscilloscope-like analog displays.

Integrated circuit memory was the booster rocket computer graphics needed to get off the ground. When MOS and later complimentary MOS (CMOS) high-density memories began to appear things changed very quickly in the computer industry. Small, low cost, xMOS memory was the primary enabler of the minicomputer and then the PC industry and computer graphics.

In 1969 - Bell Labs built the first frame buffer using some of the first semiconductors. It was an amazing 3 bits deep and represented a fully digital storage of a displayable image (displayable on a vector screen. We now had a hybrid pixel, part digital, part analog. The system was used to demonstrate a Paint program developed by Noll and Miller at, Bell Labs in 1969.

Digital Raster Displays

A few years later, in 1972, Ramtek developed a commercial product using the technique and so gets credited with the first commercial digital frame buffer. Like the Bell Labs unit, the frame buffer was built using integrated circuit shift registers.

One year later, in 1973 an electronic hobbyist, Don Lancaster, wrote an article on, "The TV Typewriter." Lancaster's design provided the first display of alphanumeric information on an ordinary television set. It used $120 worth of electronics components, as outlined in the September 1973 issue of Radio Electronics. The original design included two memory boards and could generate and store 512 characters as 16 lines of 32 characters. A 90-minute cassette tape provided supplementary storage for about 100 pages of text.

The Digital Equipment Corporation, DEC introduced their PDP8 computer in 1968. By late 1973, the PDP-8 family was the best selling computer in the world. The PDP-8 has been described as the model-T of the computer industry because it was the first computer to be mass-produced at a cost that just about anyone could afford (at least with company money). The PDP 8 is (people still have and use them) a 12 bit single accumulator machine which can address up to 32K 12 bit words. It used semiconductor memory and had a character-based raster display.

That same year digital raster displays appeared simultaneously in several places. In1973 E&S began marketing first commercial frame buffer. And Richard Shoup, at PARC showed his raster display and digital frame buffer that was developed for painting software for graphic arts and used a program called Paint, that was developed by Alvy Ray. The resulting SuperPaint system now resides in the Computer Museum History Center collection at Moffett Field in Mountain View, California. Richard Shoup got his BSEE in 1965 and Ph.D. in Computer Science in 1970 at Carnegie Mellon University in Pittsburgh under advisor and computer industry guru Gordon Bell, one of the founders of DEC. PARC was a prolific place for computer graphics in those days and created the bit-mapped display Alto computer, designed by Thacker in February 1973.

So depending on how you want to define it, the pixel was born sometime between Sutherland's experiments with his Sketchpad in 1963 and the commercial raster-scan graphics displays from DEC and Xerox in 1973.

Today they permeate our lives in almost everything we do, whether we're checking the time on our digital watch, or our cell phone, or our e-mail on our computer, or our PDA, or the speed of our car or its gasoline level in our cars, or the airline delay at the airport, or the train delay, or the caller ID, or the temperature of the coffee in our digital controlled coffee maker. Pixels are The source of information delivery, they are our final fantasy (yeah, that's pixels too).