Who Invented the Computer? Ivan Sutherland and Sketchpad

Who Invented the Computer? This is the twenty-first installment in our ongoing series.

Sir Isaac Newton's dictum about "standing on the shoulders of giants" applies across every field of human endeavor as curious and determined individuals tinker with existing inventions and concepts to create something new and better. This was especially true in 1963 when PhD candidate Ivan Sutherland utilized a number of existing technologies to launch a new era in human-computer interaction with the creation of Sketchpad, the world's first interactive computer graphics program.

Sutherland was an intern at Lincoln Labs at the Massachusetts Institute of Technology (MIT), where he worked on the TX-0, a computer optimized for researching human-computer interaction. One day, while working with a relatively new MIT invention, the Light Pen, to plot points on the TX-0's cathode ray tube ("CRT") display, Sutherland hit upon the idea of using computers to draw. Until this time, engineers and architects had drawn their designs by hand, a painstaking and arduous process.

Make My PhD

Sutherland approached his advisor, Wes Clark with the idea of writing such a program as part of his thesis. Clark quickly agreed and offered the school's more powerful experimental computer, the TX-2, which Clark had built in 1958. The TX-2, one of the first-generation electronic digital computers in which transistors replaced vacuum tubes, was specifically designed to aid in the effort to enhance the study of real-time human-computer interaction.

It was also one of the largest and most powerful computers in the world. Besides filling a large room, it had 320 kilobytes (KB) of memory, twice the capacity of the largest commercial machines then on the market. And critically, for Sutherland's purposes, it also featured a 7-inch cathode ray tube display and a light pen for interacting with the display.

In less than a year Sutherland had a working version of the program he called "Sketchpad." This first version enabled the operator to use the light pen to draw vertical and horizontal lines on the CRT. Flipping a variety of toggle switches on console enabled the operator to give direct instructions to the computer concerning the size and ratio of each drawn line.

Following suggestions from members of his thesis committee, Sutherland's final version of the program incorporated the concepts of plex-programming, an early form of real-time programming, and Bootstrap Picture Language to make drawn images responsive.

Not Ready for Prime Time

Sketchpad proved to be a hit when Sutherland displayed it at MIT's Joint Computer Conference in the spring of 1963. Operators could not only draw lines with the program, but with the flip of a switch, convert rough drawings into neat looking figures and shapes. Drawn figures could also be stored in memory, copied, moved, rotated, zoomed in and out on and even resized while retaining their basic properties of width, length, and angles as well as any hidden lines.

If the user decided to make a change to a drawing, they could make the same change to any existing copies of the drawing as well.

Although Sketchpad was not an actual computer-aided design program, it was a working proof-of-concept that humans could communicate and interact directly with computers. Prior to this time, computers were programmed to perform specific functions by typing in lengthy written statements consisting of letters and numbers.

Sutherland's program did more than demonstrate human-computer interaction. In the process of designing Sketchpad, he also accomplished three firsts in computing concepts that remain essential components of today's computers, tablets, and smartphones: the graphical user interface ("GUI"), object-oriented programming, and non-procedural programming.

In spite of Sketchpad's impressive performance, Sutherland did not conceive of it as a viable commercial product for a number of reasons: First, the program was designed exclusively for the TX-2 � a non-commercial research computer � and it would have been difficult to modify to run on a commercial machine. Second, few commercial computers at that time had the computing capacity to run Sketchpad. Third, the cost of computing was still extremely high. And fourth, the hardware for good graphic displays was still years away.

What You Don't Know ...

Sutherland would go on to have an impressive career teaching at a number of prestigious institutions including Harvard University, California Institute of Technology, and the University of Utah. In 1968 he cofounded the Evans & Sutherland Corporation to focus on the fields of real-time hardware and accelerated 3D computer graphics. For his work on Sketchpad, he would receive the A.M. Turing Award and John von Neumann Medal in 1988, and the Kyoto Prize in 2012.

Sketchpad would prove to be the foundation for two future developments in the field of computer graphics including Computer-Aided Design ("CAD") software and the oN-Line System  (NLS) that employed hypertext links, screen windowing, presentation programs and other modern-day computing concepts. Just as importantly, he introduced the idea of using computers for art and design instead of just scientific and technical work.

While Sutherland did indeed stand on the shoulders of those who came before, he remained humble about his work. Later in life, he was asked how he was "able to create the first interactive graphics program, the first non-procedural programming language, and the first object-oriented software system in less than one year?"

His answer: "Well, I didn't know it was hard."